diff --git a/docs/archive/slides/index.html b/docs/archive/slides/index.html
index 6954d1b24..7e3f058b2 100644
--- a/docs/archive/slides/index.html
+++ b/docs/archive/slides/index.html
@@ -4,7 +4,7 @@
   <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
   <meta name="viewport" content="width=device-width, initial-scale=1">
   <meta name="repo" content="https://github.com/gvwilson/sd4ds">
-  <meta name="build_date" content="2023-06-02">
+  <meta name="build_date" content="2023-06-03">
   <meta name="template" content="slides">
   <meta name="major" content="Chapter 9">
   
@@ -443,7 +443,6 @@ <h1>A File Archiver</h1>
 [lorgat_tutorial]: https://wasimlorgat.com/posts/editor.html
 [lorgat_wasim]: https://wasimlorgat.com/
 [marthas_rules]: https://journals.sagepub.com/doi/10.1177/088610998600100206
-[mkdocs]: https://www.mkdocs.org/
 [nison_mael]: https://arcanis.github.io/
 [nystrom_bob]: http://journal.stuffwithstuff.com/
 [package_manager_tutorial]: https://classic.yarnpkg.com/blog/2017/07/11/lets-dev-a-package-manager/
@@ -458,6 +457,7 @@ <h1>A File Archiver</h1>
 [py_ast]: https://docs.python.org/3/library/ast.html
 [py_chainmap]: https://docs.python.org/3/library/collections.html#collections.ChainMap
 [py_cprofile]: https://docs.python.org/3/library/profile.html
+[py_fractions]: https://docs.python.org/3/library/fractions.html
 [py_glob]: https://docs.python.org/3/library/glob.html
 [py_hashlib]: https://docs.python.org/3/library/hashlib.html
 [py_inspect]: https://docs.python.org/3/library/inspect.html
@@ -465,15 +465,16 @@ <h1>A File Archiver</h1>
 [py_itertools]: https://docs.python.org/3/library/itertools.html
 [py_json]: https://docs.python.org/3/library/json.html
 [py_jsonschema]: https://python-jsonschema.readthedocs.io/
-[py_metaclass]: https://docs.python.org/3/reference/datamodel.html#metaclasses
 [py_mimetypes]: https://docs.python.org/3/library/mimetypes.html
 [py_pickle]: https://docs.python.org/3/library/pickle.html
 [py_property]: https://docs.python.org/3/library/functions.html#property
 [py_semver]: https://pypi.org/project/semantic-version/
+[py_struct]: https://docs.python.org/3/library/struct.html
 [py_textwrap]: https://docs.python.org/3/library/textwrap.html
 [py_urlparse]: https://docs.python.org/3/library/urllib.parse.html
 [pyfakefs]: https://pytest-pyfakefs.readthedocs.io/
 [pytest]: https://docs.pytest.org/
+[pytest_approx]: https://docs.pytest.org/en/4.6.x/reference.html#pytest-approx
 [python]: https://www.python.org/
 [reim_michael]: https://elderlinux.org/
 [requests]: https://requests.readthedocs.io/
@@ -481,13 +482,15 @@ <h1>A File Archiver</h1>
 [selenium]: https://www.selenium.dev/
 [semver_spec]: https://semver.org/
 [sinel_joseph]: https://en.wikipedia.org/wiki/Joseph_Claude_Sinel
-[sphinx]: https://www.sphinx-doc.org/
+[snakemake]: https://snakemake.readthedocs.io/
 [sqlite]: https://sqlite.org/
 [stack_connor]: https://connorstack.com/
 [svg_screenshot]: https://chrome.google.com/webstore/detail/svg-screenshot/nfakpcpmhhilkdpphcjgnokknpbpdllg
 [t3_personas]: https://teachtogether.tech/en/index.html#s:process-personas
+[textualize_fraction]: https://www.textualize.io/blog/posts/7-things-about-terminals
 [udhr]: https://www.un.org/en/universal-declaration-human-rights/
 [ungc]: https://www.unglobalcompact.org/what-is-gc/mission/principles
+[unicode]: https://www.unicode.org/
 [unix_glob]: https://en.wikipedia.org/wiki/Glob_(programming)
 [unix_packaging]: https://eerielinux.wordpress.com/2017/08/15/the-history-of-nix-package-management/
 [webaim_wave]: https://wave.webaim.org/
diff --git a/docs/binary/index.html b/docs/binary/index.html
index 9475d210e..d2c9c649f 100644
--- a/docs/binary/index.html
+++ b/docs/binary/index.html
@@ -4,7 +4,7 @@
   <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
   <meta name="viewport" content="width=device-width, initial-scale=1">
   <meta name="repo" content="https://github.com/gvwilson/sd4ds">
-  <meta name="build_date" content="2023-06-02">
+  <meta name="build_date" content="2023-06-03">
   <meta name="template" content="default">
   <meta name="major" content="Chapter 17">
   <meta name="has_slides" content="true">
@@ -675,7 +675,7 @@ <h2 id="binary-text">Section 17.3: Text</h2>
 U+0065 for an upper-case Latin &ldquo;A&rdquo;,
 U+2605 for a black star,
 and so on.
-(The [Unicode Consortium site][unicode] offers a complete list.)</p>
+(The <a href="https://www.unicode.org/">Unicode Consortium site</a> offers a complete list.)</p>
 <p>The second part defined ways to store these values in memory.
 The simplest of these is <a class="gl-ref" href="../glossary/#utf_32" markdown="1">UTF-32</a>,
 which stores every character as a 32-bit number.
@@ -838,7 +838,7 @@ <h2 id="binary-binary">Section 17.4: And Now, Persistence</h2>
 <figcaption markdown="1">Figure 17.3: Packing and unpacking binary values.</figcaption>
 </figure>
 
-<p>Python&rsquo;s [struct][py_struct] module packs and unpacks data for us.
+<p>Python&rsquo;s <a href="https://docs.python.org/3/library/struct.html">struct</a> module packs and unpacks data for us.
 The function <code>pack(format, val_1, val_2, …)</code>
 takes a format string and a bunch of values as arguments
 and packs them into a <code>bytes</code> object.
@@ -1173,13 +1173,13 @@ <h3>Go To the Source</h3>
 though,
 since they don&rsquo;t depend on being the same down to the last bit.</p>
 <p>If we do want to compare floating point numbers
-we can use something like [the <code>approx</code> class][pytest_approx] from <a href="https://docs.pytest.org/">pytest</a>
+we can use something like <a href="https://docs.pytest.org/en/4.6.x/reference.html#pytest-approx">the <code>approx</code> class</a> from <a href="https://docs.pytest.org/">pytest</a>
 which checks whether two numbers are within some tolerance of each other.
 A completely different approach is to use something like
-the [fractions][py_fractions] module,
+the <a href="https://docs.python.org/3/library/fractions.html">fractions</a> module,
 which (as its name suggests) uses numerators and denominators
 to avoid some precision issues.
-[This post][textualize_fraction] describes one clever use of the module.</p>
+<a href="https://www.textualize.io/blog/posts/7-things-about-terminals">This post</a> describes one clever use of the module.</p>
 <h2 id="binary-summary">Section 17.6: Summary</h2>
 <figure id="binary-concept-map">
 <img src="./concept_map.svg" alt="Concept map for binary data"/>
@@ -1237,7 +1237,7 @@ <h3 class="exercise">Roundoff</h3>
 <li>Calculate the absolute and relative differences between corresponding values
     (which should be identical).</li>
 <li>Repeat the exercise using the <code>Fraction</code> class
-    from the [fractions][py_fractions] module.</li>
+    from the <a href="https://docs.python.org/3/library/fractions.html">fractions</a> module.</li>
 </ol>
         </main>
       </div>
diff --git a/docs/binary/slides/index.html b/docs/binary/slides/index.html
index 4bf547119..5681aa2ac 100644
--- a/docs/binary/slides/index.html
+++ b/docs/binary/slides/index.html
@@ -4,7 +4,7 @@
   <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
   <meta name="viewport" content="width=device-width, initial-scale=1">
   <meta name="repo" content="https://github.com/gvwilson/sd4ds">
-  <meta name="build_date" content="2023-06-02">
+  <meta name="build_date" content="2023-06-03">
   <meta name="template" content="slides">
   <meta name="major" content="Chapter 17">
   
@@ -499,7 +499,6 @@ <h1>Binary Data</h1>
 [lorgat_tutorial]: https://wasimlorgat.com/posts/editor.html
 [lorgat_wasim]: https://wasimlorgat.com/
 [marthas_rules]: https://journals.sagepub.com/doi/10.1177/088610998600100206
-[mkdocs]: https://www.mkdocs.org/
 [nison_mael]: https://arcanis.github.io/
 [nystrom_bob]: http://journal.stuffwithstuff.com/
 [package_manager_tutorial]: https://classic.yarnpkg.com/blog/2017/07/11/lets-dev-a-package-manager/
@@ -514,6 +513,7 @@ <h1>Binary Data</h1>
 [py_ast]: https://docs.python.org/3/library/ast.html
 [py_chainmap]: https://docs.python.org/3/library/collections.html#collections.ChainMap
 [py_cprofile]: https://docs.python.org/3/library/profile.html
+[py_fractions]: https://docs.python.org/3/library/fractions.html
 [py_glob]: https://docs.python.org/3/library/glob.html
 [py_hashlib]: https://docs.python.org/3/library/hashlib.html
 [py_inspect]: https://docs.python.org/3/library/inspect.html
@@ -521,15 +521,16 @@ <h1>Binary Data</h1>
 [py_itertools]: https://docs.python.org/3/library/itertools.html
 [py_json]: https://docs.python.org/3/library/json.html
 [py_jsonschema]: https://python-jsonschema.readthedocs.io/
-[py_metaclass]: https://docs.python.org/3/reference/datamodel.html#metaclasses
 [py_mimetypes]: https://docs.python.org/3/library/mimetypes.html
 [py_pickle]: https://docs.python.org/3/library/pickle.html
 [py_property]: https://docs.python.org/3/library/functions.html#property
 [py_semver]: https://pypi.org/project/semantic-version/
+[py_struct]: https://docs.python.org/3/library/struct.html
 [py_textwrap]: https://docs.python.org/3/library/textwrap.html
 [py_urlparse]: https://docs.python.org/3/library/urllib.parse.html
 [pyfakefs]: https://pytest-pyfakefs.readthedocs.io/
 [pytest]: https://docs.pytest.org/
+[pytest_approx]: https://docs.pytest.org/en/4.6.x/reference.html#pytest-approx
 [python]: https://www.python.org/
 [reim_michael]: https://elderlinux.org/
 [requests]: https://requests.readthedocs.io/
@@ -537,13 +538,15 @@ <h1>Binary Data</h1>
 [selenium]: https://www.selenium.dev/
 [semver_spec]: https://semver.org/
 [sinel_joseph]: https://en.wikipedia.org/wiki/Joseph_Claude_Sinel
-[sphinx]: https://www.sphinx-doc.org/
+[snakemake]: https://snakemake.readthedocs.io/
 [sqlite]: https://sqlite.org/
 [stack_connor]: https://connorstack.com/
 [svg_screenshot]: https://chrome.google.com/webstore/detail/svg-screenshot/nfakpcpmhhilkdpphcjgnokknpbpdllg
 [t3_personas]: https://teachtogether.tech/en/index.html#s:process-personas
+[textualize_fraction]: https://www.textualize.io/blog/posts/7-things-about-terminals
 [udhr]: https://www.un.org/en/universal-declaration-human-rights/
 [ungc]: https://www.unglobalcompact.org/what-is-gc/mission/principles
+[unicode]: https://www.unicode.org/
 [unix_glob]: https://en.wikipedia.org/wiki/Glob_(programming)
 [unix_packaging]: https://eerielinux.wordpress.com/2017/08/15/the-history-of-nix-package-management/
 [webaim_wave]: https://wave.webaim.org/
diff --git a/docs/build/index.html b/docs/build/index.html
index e3048cdef..c6ea6ac88 100644
--- a/docs/build/index.html
+++ b/docs/build/index.html
@@ -4,7 +4,7 @@
   <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
   <meta name="viewport" content="width=device-width, initial-scale=1">
   <meta name="repo" content="https://github.com/gvwilson/sd4ds">
-  <meta name="build_date" content="2023-06-02">
+  <meta name="build_date" content="2023-06-03">
   <meta name="template" content="default">
   <meta name="major" content="Chapter 19">
   <meta name="has_slides" content="true">
@@ -358,7 +358,7 @@ <h1>Chapter 19: A Build Manager</h1>
 to keep track of which files depend on which
 and what actions to take to create or update files.
 The first tool of this kind was <a href="https://www.gnu.org/software/make/">Make</a>,
-but many others now exist (such as [Snakemake][snakemake]).
+but many others now exist (such as <a href="https://snakemake.readthedocs.io/">Snakemake</a>).
 If a <a class="gl-ref" href="../glossary/#build_target" markdown="1">target</a> is <a class="gl-ref" href="../glossary/#build_stale" markdown="1">stale</a>
 with respect to any of its  <a class="gl-ref" href="../glossary/#dependency" markdown="1">dependencies</a>,
 the builder manager runs a <a class="gl-ref" href="../glossary/#build_recipe" markdown="1">recipe</a> to refresh it.</p>
diff --git a/docs/build/slides/index.html b/docs/build/slides/index.html
index 224d54d44..dfeee403f 100644
--- a/docs/build/slides/index.html
+++ b/docs/build/slides/index.html
@@ -4,7 +4,7 @@
   <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
   <meta name="viewport" content="width=device-width, initial-scale=1">
   <meta name="repo" content="https://github.com/gvwilson/sd4ds">
-  <meta name="build_date" content="2023-06-02">
+  <meta name="build_date" content="2023-06-03">
   <meta name="template" content="slides">
   <meta name="major" content="Chapter 19">
   
@@ -455,7 +455,6 @@ <h1>A Build Manager</h1>
 [lorgat_tutorial]: https://wasimlorgat.com/posts/editor.html
 [lorgat_wasim]: https://wasimlorgat.com/
 [marthas_rules]: https://journals.sagepub.com/doi/10.1177/088610998600100206
-[mkdocs]: https://www.mkdocs.org/
 [nison_mael]: https://arcanis.github.io/
 [nystrom_bob]: http://journal.stuffwithstuff.com/
 [package_manager_tutorial]: https://classic.yarnpkg.com/blog/2017/07/11/lets-dev-a-package-manager/
@@ -470,6 +469,7 @@ <h1>A Build Manager</h1>
 [py_ast]: https://docs.python.org/3/library/ast.html
 [py_chainmap]: https://docs.python.org/3/library/collections.html#collections.ChainMap
 [py_cprofile]: https://docs.python.org/3/library/profile.html
+[py_fractions]: https://docs.python.org/3/library/fractions.html
 [py_glob]: https://docs.python.org/3/library/glob.html
 [py_hashlib]: https://docs.python.org/3/library/hashlib.html
 [py_inspect]: https://docs.python.org/3/library/inspect.html
@@ -477,15 +477,16 @@ <h1>A Build Manager</h1>
 [py_itertools]: https://docs.python.org/3/library/itertools.html
 [py_json]: https://docs.python.org/3/library/json.html
 [py_jsonschema]: https://python-jsonschema.readthedocs.io/
-[py_metaclass]: https://docs.python.org/3/reference/datamodel.html#metaclasses
 [py_mimetypes]: https://docs.python.org/3/library/mimetypes.html
 [py_pickle]: https://docs.python.org/3/library/pickle.html
 [py_property]: https://docs.python.org/3/library/functions.html#property
 [py_semver]: https://pypi.org/project/semantic-version/
+[py_struct]: https://docs.python.org/3/library/struct.html
 [py_textwrap]: https://docs.python.org/3/library/textwrap.html
 [py_urlparse]: https://docs.python.org/3/library/urllib.parse.html
 [pyfakefs]: https://pytest-pyfakefs.readthedocs.io/
 [pytest]: https://docs.pytest.org/
+[pytest_approx]: https://docs.pytest.org/en/4.6.x/reference.html#pytest-approx
 [python]: https://www.python.org/
 [reim_michael]: https://elderlinux.org/
 [requests]: https://requests.readthedocs.io/
@@ -493,13 +494,15 @@ <h1>A Build Manager</h1>
 [selenium]: https://www.selenium.dev/
 [semver_spec]: https://semver.org/
 [sinel_joseph]: https://en.wikipedia.org/wiki/Joseph_Claude_Sinel
-[sphinx]: https://www.sphinx-doc.org/
+[snakemake]: https://snakemake.readthedocs.io/
 [sqlite]: https://sqlite.org/
 [stack_connor]: https://connorstack.com/
 [svg_screenshot]: https://chrome.google.com/webstore/detail/svg-screenshot/nfakpcpmhhilkdpphcjgnokknpbpdllg
 [t3_personas]: https://teachtogether.tech/en/index.html#s:process-personas
+[textualize_fraction]: https://www.textualize.io/blog/posts/7-things-about-terminals
 [udhr]: https://www.un.org/en/universal-declaration-human-rights/
 [ungc]: https://www.unglobalcompact.org/what-is-gc/mission/principles
+[unicode]: https://www.unicode.org/
 [unix_glob]: https://en.wikipedia.org/wiki/Glob_(programming)
 [unix_packaging]: https://eerielinux.wordpress.com/2017/08/15/the-history-of-nix-package-management/
 [webaim_wave]: https://wave.webaim.org/
diff --git a/docs/check/slides/index.html b/docs/check/slides/index.html
index c1a0cca4e..efeca62ed 100644
--- a/docs/check/slides/index.html
+++ b/docs/check/slides/index.html
@@ -4,7 +4,7 @@
   <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
   <meta name="viewport" content="width=device-width, initial-scale=1">
   <meta name="repo" content="https://github.com/gvwilson/sd4ds">
-  <meta name="build_date" content="2023-06-02">
+  <meta name="build_date" content="2023-06-03">
   <meta name="template" content="slides">
   <meta name="major" content="Chapter 11">
   
@@ -490,7 +490,6 @@ <h1>Main Title</h1>
 [lorgat_tutorial]: https://wasimlorgat.com/posts/editor.html
 [lorgat_wasim]: https://wasimlorgat.com/
 [marthas_rules]: https://journals.sagepub.com/doi/10.1177/088610998600100206
-[mkdocs]: https://www.mkdocs.org/
 [nison_mael]: https://arcanis.github.io/
 [nystrom_bob]: http://journal.stuffwithstuff.com/
 [package_manager_tutorial]: https://classic.yarnpkg.com/blog/2017/07/11/lets-dev-a-package-manager/
@@ -505,6 +504,7 @@ <h1>Main Title</h1>
 [py_ast]: https://docs.python.org/3/library/ast.html
 [py_chainmap]: https://docs.python.org/3/library/collections.html#collections.ChainMap
 [py_cprofile]: https://docs.python.org/3/library/profile.html
+[py_fractions]: https://docs.python.org/3/library/fractions.html
 [py_glob]: https://docs.python.org/3/library/glob.html
 [py_hashlib]: https://docs.python.org/3/library/hashlib.html
 [py_inspect]: https://docs.python.org/3/library/inspect.html
@@ -512,15 +512,16 @@ <h1>Main Title</h1>
 [py_itertools]: https://docs.python.org/3/library/itertools.html
 [py_json]: https://docs.python.org/3/library/json.html
 [py_jsonschema]: https://python-jsonschema.readthedocs.io/
-[py_metaclass]: https://docs.python.org/3/reference/datamodel.html#metaclasses
 [py_mimetypes]: https://docs.python.org/3/library/mimetypes.html
 [py_pickle]: https://docs.python.org/3/library/pickle.html
 [py_property]: https://docs.python.org/3/library/functions.html#property
 [py_semver]: https://pypi.org/project/semantic-version/
+[py_struct]: https://docs.python.org/3/library/struct.html
 [py_textwrap]: https://docs.python.org/3/library/textwrap.html
 [py_urlparse]: https://docs.python.org/3/library/urllib.parse.html
 [pyfakefs]: https://pytest-pyfakefs.readthedocs.io/
 [pytest]: https://docs.pytest.org/
+[pytest_approx]: https://docs.pytest.org/en/4.6.x/reference.html#pytest-approx
 [python]: https://www.python.org/
 [reim_michael]: https://elderlinux.org/
 [requests]: https://requests.readthedocs.io/
@@ -528,13 +529,15 @@ <h1>Main Title</h1>
 [selenium]: https://www.selenium.dev/
 [semver_spec]: https://semver.org/
 [sinel_joseph]: https://en.wikipedia.org/wiki/Joseph_Claude_Sinel
-[sphinx]: https://www.sphinx-doc.org/
+[snakemake]: https://snakemake.readthedocs.io/
 [sqlite]: https://sqlite.org/
 [stack_connor]: https://connorstack.com/
 [svg_screenshot]: https://chrome.google.com/webstore/detail/svg-screenshot/nfakpcpmhhilkdpphcjgnokknpbpdllg
 [t3_personas]: https://teachtogether.tech/en/index.html#s:process-personas
+[textualize_fraction]: https://www.textualize.io/blog/posts/7-things-about-terminals
 [udhr]: https://www.un.org/en/universal-declaration-human-rights/
 [ungc]: https://www.unglobalcompact.org/what-is-gc/mission/principles
+[unicode]: https://www.unicode.org/
 [unix_glob]: https://en.wikipedia.org/wiki/Glob_(programming)
 [unix_packaging]: https://eerielinux.wordpress.com/2017/08/15/the-history-of-nix-package-management/
 [webaim_wave]: https://wave.webaim.org/
diff --git a/docs/db/slides/index.html b/docs/db/slides/index.html
index 5f9dc7a13..a933ceb29 100644
--- a/docs/db/slides/index.html
+++ b/docs/db/slides/index.html
@@ -4,7 +4,7 @@
   <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
   <meta name="viewport" content="width=device-width, initial-scale=1">
   <meta name="repo" content="https://github.com/gvwilson/sd4ds">
-  <meta name="build_date" content="2023-06-02">
+  <meta name="build_date" content="2023-06-03">
   <meta name="template" content="slides">
   <meta name="major" content="Chapter 18">
   
@@ -670,7 +670,6 @@ <h1>A Database</h1>
 [lorgat_tutorial]: https://wasimlorgat.com/posts/editor.html
 [lorgat_wasim]: https://wasimlorgat.com/
 [marthas_rules]: https://journals.sagepub.com/doi/10.1177/088610998600100206
-[mkdocs]: https://www.mkdocs.org/
 [nison_mael]: https://arcanis.github.io/
 [nystrom_bob]: http://journal.stuffwithstuff.com/
 [package_manager_tutorial]: https://classic.yarnpkg.com/blog/2017/07/11/lets-dev-a-package-manager/
@@ -685,6 +684,7 @@ <h1>A Database</h1>
 [py_ast]: https://docs.python.org/3/library/ast.html
 [py_chainmap]: https://docs.python.org/3/library/collections.html#collections.ChainMap
 [py_cprofile]: https://docs.python.org/3/library/profile.html
+[py_fractions]: https://docs.python.org/3/library/fractions.html
 [py_glob]: https://docs.python.org/3/library/glob.html
 [py_hashlib]: https://docs.python.org/3/library/hashlib.html
 [py_inspect]: https://docs.python.org/3/library/inspect.html
@@ -692,15 +692,16 @@ <h1>A Database</h1>
 [py_itertools]: https://docs.python.org/3/library/itertools.html
 [py_json]: https://docs.python.org/3/library/json.html
 [py_jsonschema]: https://python-jsonschema.readthedocs.io/
-[py_metaclass]: https://docs.python.org/3/reference/datamodel.html#metaclasses
 [py_mimetypes]: https://docs.python.org/3/library/mimetypes.html
 [py_pickle]: https://docs.python.org/3/library/pickle.html
 [py_property]: https://docs.python.org/3/library/functions.html#property
 [py_semver]: https://pypi.org/project/semantic-version/
+[py_struct]: https://docs.python.org/3/library/struct.html
 [py_textwrap]: https://docs.python.org/3/library/textwrap.html
 [py_urlparse]: https://docs.python.org/3/library/urllib.parse.html
 [pyfakefs]: https://pytest-pyfakefs.readthedocs.io/
 [pytest]: https://docs.pytest.org/
+[pytest_approx]: https://docs.pytest.org/en/4.6.x/reference.html#pytest-approx
 [python]: https://www.python.org/
 [reim_michael]: https://elderlinux.org/
 [requests]: https://requests.readthedocs.io/
@@ -708,13 +709,15 @@ <h1>A Database</h1>
 [selenium]: https://www.selenium.dev/
 [semver_spec]: https://semver.org/
 [sinel_joseph]: https://en.wikipedia.org/wiki/Joseph_Claude_Sinel
-[sphinx]: https://www.sphinx-doc.org/
+[snakemake]: https://snakemake.readthedocs.io/
 [sqlite]: https://sqlite.org/
 [stack_connor]: https://connorstack.com/
 [svg_screenshot]: https://chrome.google.com/webstore/detail/svg-screenshot/nfakpcpmhhilkdpphcjgnokknpbpdllg
 [t3_personas]: https://teachtogether.tech/en/index.html#s:process-personas
+[textualize_fraction]: https://www.textualize.io/blog/posts/7-things-about-terminals
 [udhr]: https://www.un.org/en/universal-declaration-human-rights/
 [ungc]: https://www.unglobalcompact.org/what-is-gc/mission/principles
+[unicode]: https://www.unicode.org/
 [unix_glob]: https://en.wikipedia.org/wiki/Glob_(programming)
 [unix_packaging]: https://eerielinux.wordpress.com/2017/08/15/the-history-of-nix-package-management/
 [webaim_wave]: https://wave.webaim.org/
diff --git a/docs/debugger/slides/index.html b/docs/debugger/slides/index.html
index 4bef4e83e..2bb64aa33 100644
--- a/docs/debugger/slides/index.html
+++ b/docs/debugger/slides/index.html
@@ -4,7 +4,7 @@
   <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
   <meta name="viewport" content="width=device-width, initial-scale=1">
   <meta name="repo" content="https://github.com/gvwilson/sd4ds">
-  <meta name="build_date" content="2023-06-02">
+  <meta name="build_date" content="2023-06-03">
   <meta name="template" content="slides">
   <meta name="major" content="Chapter 26">
   
@@ -526,7 +526,6 @@ <h1>A Debugger</h1>
 [lorgat_tutorial]: https://wasimlorgat.com/posts/editor.html
 [lorgat_wasim]: https://wasimlorgat.com/
 [marthas_rules]: https://journals.sagepub.com/doi/10.1177/088610998600100206
-[mkdocs]: https://www.mkdocs.org/
 [nison_mael]: https://arcanis.github.io/
 [nystrom_bob]: http://journal.stuffwithstuff.com/
 [package_manager_tutorial]: https://classic.yarnpkg.com/blog/2017/07/11/lets-dev-a-package-manager/
@@ -541,6 +540,7 @@ <h1>A Debugger</h1>
 [py_ast]: https://docs.python.org/3/library/ast.html
 [py_chainmap]: https://docs.python.org/3/library/collections.html#collections.ChainMap
 [py_cprofile]: https://docs.python.org/3/library/profile.html
+[py_fractions]: https://docs.python.org/3/library/fractions.html
 [py_glob]: https://docs.python.org/3/library/glob.html
 [py_hashlib]: https://docs.python.org/3/library/hashlib.html
 [py_inspect]: https://docs.python.org/3/library/inspect.html
@@ -548,15 +548,16 @@ <h1>A Debugger</h1>
 [py_itertools]: https://docs.python.org/3/library/itertools.html
 [py_json]: https://docs.python.org/3/library/json.html
 [py_jsonschema]: https://python-jsonschema.readthedocs.io/
-[py_metaclass]: https://docs.python.org/3/reference/datamodel.html#metaclasses
 [py_mimetypes]: https://docs.python.org/3/library/mimetypes.html
 [py_pickle]: https://docs.python.org/3/library/pickle.html
 [py_property]: https://docs.python.org/3/library/functions.html#property
 [py_semver]: https://pypi.org/project/semantic-version/
+[py_struct]: https://docs.python.org/3/library/struct.html
 [py_textwrap]: https://docs.python.org/3/library/textwrap.html
 [py_urlparse]: https://docs.python.org/3/library/urllib.parse.html
 [pyfakefs]: https://pytest-pyfakefs.readthedocs.io/
 [pytest]: https://docs.pytest.org/
+[pytest_approx]: https://docs.pytest.org/en/4.6.x/reference.html#pytest-approx
 [python]: https://www.python.org/
 [reim_michael]: https://elderlinux.org/
 [requests]: https://requests.readthedocs.io/
@@ -564,13 +565,15 @@ <h1>A Debugger</h1>
 [selenium]: https://www.selenium.dev/
 [semver_spec]: https://semver.org/
 [sinel_joseph]: https://en.wikipedia.org/wiki/Joseph_Claude_Sinel
-[sphinx]: https://www.sphinx-doc.org/
+[snakemake]: https://snakemake.readthedocs.io/
 [sqlite]: https://sqlite.org/
 [stack_connor]: https://connorstack.com/
 [svg_screenshot]: https://chrome.google.com/webstore/detail/svg-screenshot/nfakpcpmhhilkdpphcjgnokknpbpdllg
 [t3_personas]: https://teachtogether.tech/en/index.html#s:process-personas
+[textualize_fraction]: https://www.textualize.io/blog/posts/7-things-about-terminals
 [udhr]: https://www.un.org/en/universal-declaration-human-rights/
 [ungc]: https://www.unglobalcompact.org/what-is-gc/mission/principles
+[unicode]: https://www.unicode.org/
 [unix_glob]: https://en.wikipedia.org/wiki/Glob_(programming)
 [unix_packaging]: https://eerielinux.wordpress.com/2017/08/15/the-history-of-nix-package-management/
 [webaim_wave]: https://wave.webaim.org/
diff --git a/docs/dup/slides/index.html b/docs/dup/slides/index.html
index 35e87f97f..2948b502f 100644
--- a/docs/dup/slides/index.html
+++ b/docs/dup/slides/index.html
@@ -4,7 +4,7 @@
   <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
   <meta name="viewport" content="width=device-width, initial-scale=1">
   <meta name="repo" content="https://github.com/gvwilson/sd4ds">
-  <meta name="build_date" content="2023-06-02">
+  <meta name="build_date" content="2023-06-03">
   <meta name="template" content="slides">
   <meta name="major" content="Chapter 2">
   
@@ -494,7 +494,6 @@ <h1>Finding Duplicate Files</h1>
 [lorgat_tutorial]: https://wasimlorgat.com/posts/editor.html
 [lorgat_wasim]: https://wasimlorgat.com/
 [marthas_rules]: https://journals.sagepub.com/doi/10.1177/088610998600100206
-[mkdocs]: https://www.mkdocs.org/
 [nison_mael]: https://arcanis.github.io/
 [nystrom_bob]: http://journal.stuffwithstuff.com/
 [package_manager_tutorial]: https://classic.yarnpkg.com/blog/2017/07/11/lets-dev-a-package-manager/
@@ -509,6 +508,7 @@ <h1>Finding Duplicate Files</h1>
 [py_ast]: https://docs.python.org/3/library/ast.html
 [py_chainmap]: https://docs.python.org/3/library/collections.html#collections.ChainMap
 [py_cprofile]: https://docs.python.org/3/library/profile.html
+[py_fractions]: https://docs.python.org/3/library/fractions.html
 [py_glob]: https://docs.python.org/3/library/glob.html
 [py_hashlib]: https://docs.python.org/3/library/hashlib.html
 [py_inspect]: https://docs.python.org/3/library/inspect.html
@@ -516,15 +516,16 @@ <h1>Finding Duplicate Files</h1>
 [py_itertools]: https://docs.python.org/3/library/itertools.html
 [py_json]: https://docs.python.org/3/library/json.html
 [py_jsonschema]: https://python-jsonschema.readthedocs.io/
-[py_metaclass]: https://docs.python.org/3/reference/datamodel.html#metaclasses
 [py_mimetypes]: https://docs.python.org/3/library/mimetypes.html
 [py_pickle]: https://docs.python.org/3/library/pickle.html
 [py_property]: https://docs.python.org/3/library/functions.html#property
 [py_semver]: https://pypi.org/project/semantic-version/
+[py_struct]: https://docs.python.org/3/library/struct.html
 [py_textwrap]: https://docs.python.org/3/library/textwrap.html
 [py_urlparse]: https://docs.python.org/3/library/urllib.parse.html
 [pyfakefs]: https://pytest-pyfakefs.readthedocs.io/
 [pytest]: https://docs.pytest.org/
+[pytest_approx]: https://docs.pytest.org/en/4.6.x/reference.html#pytest-approx
 [python]: https://www.python.org/
 [reim_michael]: https://elderlinux.org/
 [requests]: https://requests.readthedocs.io/
@@ -532,13 +533,15 @@ <h1>Finding Duplicate Files</h1>
 [selenium]: https://www.selenium.dev/
 [semver_spec]: https://semver.org/
 [sinel_joseph]: https://en.wikipedia.org/wiki/Joseph_Claude_Sinel
-[sphinx]: https://www.sphinx-doc.org/
+[snakemake]: https://snakemake.readthedocs.io/
 [sqlite]: https://sqlite.org/
 [stack_connor]: https://connorstack.com/
 [svg_screenshot]: https://chrome.google.com/webstore/detail/svg-screenshot/nfakpcpmhhilkdpphcjgnokknpbpdllg
 [t3_personas]: https://teachtogether.tech/en/index.html#s:process-personas
+[textualize_fraction]: https://www.textualize.io/blog/posts/7-things-about-terminals
 [udhr]: https://www.un.org/en/universal-declaration-human-rights/
 [ungc]: https://www.unglobalcompact.org/what-is-gc/mission/principles
+[unicode]: https://www.unicode.org/
 [unix_glob]: https://en.wikipedia.org/wiki/Glob_(programming)
 [unix_packaging]: https://eerielinux.wordpress.com/2017/08/15/the-history-of-nix-package-management/
 [webaim_wave]: https://wave.webaim.org/
diff --git a/docs/editor/slides/index.html b/docs/editor/slides/index.html
index 41c768186..6dfa60d92 100644
--- a/docs/editor/slides/index.html
+++ b/docs/editor/slides/index.html
@@ -4,7 +4,7 @@
   <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
   <meta name="viewport" content="width=device-width, initial-scale=1">
   <meta name="repo" content="https://github.com/gvwilson/sd4ds">
-  <meta name="build_date" content="2023-06-02">
+  <meta name="build_date" content="2023-06-03">
   <meta name="template" content="slides">
   <meta name="major" content="Chapter 23">
   
@@ -95,7 +95,6 @@ <h1>A Text Editor</h1>
 [lorgat_tutorial]: https://wasimlorgat.com/posts/editor.html
 [lorgat_wasim]: https://wasimlorgat.com/
 [marthas_rules]: https://journals.sagepub.com/doi/10.1177/088610998600100206
-[mkdocs]: https://www.mkdocs.org/
 [nison_mael]: https://arcanis.github.io/
 [nystrom_bob]: http://journal.stuffwithstuff.com/
 [package_manager_tutorial]: https://classic.yarnpkg.com/blog/2017/07/11/lets-dev-a-package-manager/
@@ -110,6 +109,7 @@ <h1>A Text Editor</h1>
 [py_ast]: https://docs.python.org/3/library/ast.html
 [py_chainmap]: https://docs.python.org/3/library/collections.html#collections.ChainMap
 [py_cprofile]: https://docs.python.org/3/library/profile.html
+[py_fractions]: https://docs.python.org/3/library/fractions.html
 [py_glob]: https://docs.python.org/3/library/glob.html
 [py_hashlib]: https://docs.python.org/3/library/hashlib.html
 [py_inspect]: https://docs.python.org/3/library/inspect.html
@@ -117,15 +117,16 @@ <h1>A Text Editor</h1>
 [py_itertools]: https://docs.python.org/3/library/itertools.html
 [py_json]: https://docs.python.org/3/library/json.html
 [py_jsonschema]: https://python-jsonschema.readthedocs.io/
-[py_metaclass]: https://docs.python.org/3/reference/datamodel.html#metaclasses
 [py_mimetypes]: https://docs.python.org/3/library/mimetypes.html
 [py_pickle]: https://docs.python.org/3/library/pickle.html
 [py_property]: https://docs.python.org/3/library/functions.html#property
 [py_semver]: https://pypi.org/project/semantic-version/
+[py_struct]: https://docs.python.org/3/library/struct.html
 [py_textwrap]: https://docs.python.org/3/library/textwrap.html
 [py_urlparse]: https://docs.python.org/3/library/urllib.parse.html
 [pyfakefs]: https://pytest-pyfakefs.readthedocs.io/
 [pytest]: https://docs.pytest.org/
+[pytest_approx]: https://docs.pytest.org/en/4.6.x/reference.html#pytest-approx
 [python]: https://www.python.org/
 [reim_michael]: https://elderlinux.org/
 [requests]: https://requests.readthedocs.io/
@@ -133,13 +134,15 @@ <h1>A Text Editor</h1>
 [selenium]: https://www.selenium.dev/
 [semver_spec]: https://semver.org/
 [sinel_joseph]: https://en.wikipedia.org/wiki/Joseph_Claude_Sinel
-[sphinx]: https://www.sphinx-doc.org/
+[snakemake]: https://snakemake.readthedocs.io/
 [sqlite]: https://sqlite.org/
 [stack_connor]: https://connorstack.com/
 [svg_screenshot]: https://chrome.google.com/webstore/detail/svg-screenshot/nfakpcpmhhilkdpphcjgnokknpbpdllg
 [t3_personas]: https://teachtogether.tech/en/index.html#s:process-personas
+[textualize_fraction]: https://www.textualize.io/blog/posts/7-things-about-terminals
 [udhr]: https://www.un.org/en/universal-declaration-human-rights/
 [ungc]: https://www.unglobalcompact.org/what-is-gc/mission/principles
+[unicode]: https://www.unicode.org/
 [unix_glob]: https://en.wikipedia.org/wiki/Glob_(programming)
 [unix_packaging]: https://eerielinux.wordpress.com/2017/08/15/the-history-of-nix-package-management/
 [webaim_wave]: https://wave.webaim.org/
diff --git a/docs/finale/slides/index.html b/docs/finale/slides/index.html
index 01c735719..8e9bc06b8 100644
--- a/docs/finale/slides/index.html
+++ b/docs/finale/slides/index.html
@@ -4,7 +4,7 @@
   <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
   <meta name="viewport" content="width=device-width, initial-scale=1">
   <meta name="repo" content="https://github.com/gvwilson/sd4ds">
-  <meta name="build_date" content="2023-06-02">
+  <meta name="build_date" content="2023-06-03">
   <meta name="template" content="slides">
   <meta name="major" content="Chapter 27">
   
@@ -146,7 +146,6 @@ <h1>Conclusion</h1>
 [lorgat_tutorial]: https://wasimlorgat.com/posts/editor.html
 [lorgat_wasim]: https://wasimlorgat.com/
 [marthas_rules]: https://journals.sagepub.com/doi/10.1177/088610998600100206
-[mkdocs]: https://www.mkdocs.org/
 [nison_mael]: https://arcanis.github.io/
 [nystrom_bob]: http://journal.stuffwithstuff.com/
 [package_manager_tutorial]: https://classic.yarnpkg.com/blog/2017/07/11/lets-dev-a-package-manager/
@@ -161,6 +160,7 @@ <h1>Conclusion</h1>
 [py_ast]: https://docs.python.org/3/library/ast.html
 [py_chainmap]: https://docs.python.org/3/library/collections.html#collections.ChainMap
 [py_cprofile]: https://docs.python.org/3/library/profile.html
+[py_fractions]: https://docs.python.org/3/library/fractions.html
 [py_glob]: https://docs.python.org/3/library/glob.html
 [py_hashlib]: https://docs.python.org/3/library/hashlib.html
 [py_inspect]: https://docs.python.org/3/library/inspect.html
@@ -168,15 +168,16 @@ <h1>Conclusion</h1>
 [py_itertools]: https://docs.python.org/3/library/itertools.html
 [py_json]: https://docs.python.org/3/library/json.html
 [py_jsonschema]: https://python-jsonschema.readthedocs.io/
-[py_metaclass]: https://docs.python.org/3/reference/datamodel.html#metaclasses
 [py_mimetypes]: https://docs.python.org/3/library/mimetypes.html
 [py_pickle]: https://docs.python.org/3/library/pickle.html
 [py_property]: https://docs.python.org/3/library/functions.html#property
 [py_semver]: https://pypi.org/project/semantic-version/
+[py_struct]: https://docs.python.org/3/library/struct.html
 [py_textwrap]: https://docs.python.org/3/library/textwrap.html
 [py_urlparse]: https://docs.python.org/3/library/urllib.parse.html
 [pyfakefs]: https://pytest-pyfakefs.readthedocs.io/
 [pytest]: https://docs.pytest.org/
+[pytest_approx]: https://docs.pytest.org/en/4.6.x/reference.html#pytest-approx
 [python]: https://www.python.org/
 [reim_michael]: https://elderlinux.org/
 [requests]: https://requests.readthedocs.io/
@@ -184,13 +185,15 @@ <h1>Conclusion</h1>
 [selenium]: https://www.selenium.dev/
 [semver_spec]: https://semver.org/
 [sinel_joseph]: https://en.wikipedia.org/wiki/Joseph_Claude_Sinel
-[sphinx]: https://www.sphinx-doc.org/
+[snakemake]: https://snakemake.readthedocs.io/
 [sqlite]: https://sqlite.org/
 [stack_connor]: https://connorstack.com/
 [svg_screenshot]: https://chrome.google.com/webstore/detail/svg-screenshot/nfakpcpmhhilkdpphcjgnokknpbpdllg
 [t3_personas]: https://teachtogether.tech/en/index.html#s:process-personas
+[textualize_fraction]: https://www.textualize.io/blog/posts/7-things-about-terminals
 [udhr]: https://www.un.org/en/universal-declaration-human-rights/
 [ungc]: https://www.unglobalcompact.org/what-is-gc/mission/principles
+[unicode]: https://www.unicode.org/
 [unix_glob]: https://en.wikipedia.org/wiki/Glob_(programming)
 [unix_packaging]: https://eerielinux.wordpress.com/2017/08/15/the-history-of-nix-package-management/
 [webaim_wave]: https://wave.webaim.org/
diff --git a/docs/ftp/slides/index.html b/docs/ftp/slides/index.html
index f42e8a67b..d2a8dbead 100644
--- a/docs/ftp/slides/index.html
+++ b/docs/ftp/slides/index.html
@@ -4,7 +4,7 @@
   <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
   <meta name="viewport" content="width=device-width, initial-scale=1">
   <meta name="repo" content="https://github.com/gvwilson/sd4ds">
-  <meta name="build_date" content="2023-06-02">
+  <meta name="build_date" content="2023-06-03">
   <meta name="template" content="slides">
   <meta name="major" content="Chapter 21">
   
@@ -252,7 +252,6 @@ <h1>Transferring Files</h1>
 [lorgat_tutorial]: https://wasimlorgat.com/posts/editor.html
 [lorgat_wasim]: https://wasimlorgat.com/
 [marthas_rules]: https://journals.sagepub.com/doi/10.1177/088610998600100206
-[mkdocs]: https://www.mkdocs.org/
 [nison_mael]: https://arcanis.github.io/
 [nystrom_bob]: http://journal.stuffwithstuff.com/
 [package_manager_tutorial]: https://classic.yarnpkg.com/blog/2017/07/11/lets-dev-a-package-manager/
@@ -267,6 +266,7 @@ <h1>Transferring Files</h1>
 [py_ast]: https://docs.python.org/3/library/ast.html
 [py_chainmap]: https://docs.python.org/3/library/collections.html#collections.ChainMap
 [py_cprofile]: https://docs.python.org/3/library/profile.html
+[py_fractions]: https://docs.python.org/3/library/fractions.html
 [py_glob]: https://docs.python.org/3/library/glob.html
 [py_hashlib]: https://docs.python.org/3/library/hashlib.html
 [py_inspect]: https://docs.python.org/3/library/inspect.html
@@ -274,15 +274,16 @@ <h1>Transferring Files</h1>
 [py_itertools]: https://docs.python.org/3/library/itertools.html
 [py_json]: https://docs.python.org/3/library/json.html
 [py_jsonschema]: https://python-jsonschema.readthedocs.io/
-[py_metaclass]: https://docs.python.org/3/reference/datamodel.html#metaclasses
 [py_mimetypes]: https://docs.python.org/3/library/mimetypes.html
 [py_pickle]: https://docs.python.org/3/library/pickle.html
 [py_property]: https://docs.python.org/3/library/functions.html#property
 [py_semver]: https://pypi.org/project/semantic-version/
+[py_struct]: https://docs.python.org/3/library/struct.html
 [py_textwrap]: https://docs.python.org/3/library/textwrap.html
 [py_urlparse]: https://docs.python.org/3/library/urllib.parse.html
 [pyfakefs]: https://pytest-pyfakefs.readthedocs.io/
 [pytest]: https://docs.pytest.org/
+[pytest_approx]: https://docs.pytest.org/en/4.6.x/reference.html#pytest-approx
 [python]: https://www.python.org/
 [reim_michael]: https://elderlinux.org/
 [requests]: https://requests.readthedocs.io/
@@ -290,13 +291,15 @@ <h1>Transferring Files</h1>
 [selenium]: https://www.selenium.dev/
 [semver_spec]: https://semver.org/
 [sinel_joseph]: https://en.wikipedia.org/wiki/Joseph_Claude_Sinel
-[sphinx]: https://www.sphinx-doc.org/
+[snakemake]: https://snakemake.readthedocs.io/
 [sqlite]: https://sqlite.org/
 [stack_connor]: https://connorstack.com/
 [svg_screenshot]: https://chrome.google.com/webstore/detail/svg-screenshot/nfakpcpmhhilkdpphcjgnokknpbpdllg
 [t3_personas]: https://teachtogether.tech/en/index.html#s:process-personas
+[textualize_fraction]: https://www.textualize.io/blog/posts/7-things-about-terminals
 [udhr]: https://www.un.org/en/universal-declaration-human-rights/
 [ungc]: https://www.unglobalcompact.org/what-is-gc/mission/principles
+[unicode]: https://www.unicode.org/
 [unix_glob]: https://en.wikipedia.org/wiki/Glob_(programming)
 [unix_packaging]: https://eerielinux.wordpress.com/2017/08/15/the-history-of-nix-package-management/
 [webaim_wave]: https://wave.webaim.org/
diff --git a/docs/func/slides/index.html b/docs/func/slides/index.html
index f5f57133e..c0473151d 100644
--- a/docs/func/slides/index.html
+++ b/docs/func/slides/index.html
@@ -4,7 +4,7 @@
   <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
   <meta name="viewport" content="width=device-width, initial-scale=1">
   <meta name="repo" content="https://github.com/gvwilson/sd4ds">
-  <meta name="build_date" content="2023-06-02">
+  <meta name="build_date" content="2023-06-03">
   <meta name="template" content="slides">
   <meta name="major" content="Chapter 7">
   
@@ -597,7 +597,6 @@ <h1>Functions and Closures</h1>
 [lorgat_tutorial]: https://wasimlorgat.com/posts/editor.html
 [lorgat_wasim]: https://wasimlorgat.com/
 [marthas_rules]: https://journals.sagepub.com/doi/10.1177/088610998600100206
-[mkdocs]: https://www.mkdocs.org/
 [nison_mael]: https://arcanis.github.io/
 [nystrom_bob]: http://journal.stuffwithstuff.com/
 [package_manager_tutorial]: https://classic.yarnpkg.com/blog/2017/07/11/lets-dev-a-package-manager/
@@ -612,6 +611,7 @@ <h1>Functions and Closures</h1>
 [py_ast]: https://docs.python.org/3/library/ast.html
 [py_chainmap]: https://docs.python.org/3/library/collections.html#collections.ChainMap
 [py_cprofile]: https://docs.python.org/3/library/profile.html
+[py_fractions]: https://docs.python.org/3/library/fractions.html
 [py_glob]: https://docs.python.org/3/library/glob.html
 [py_hashlib]: https://docs.python.org/3/library/hashlib.html
 [py_inspect]: https://docs.python.org/3/library/inspect.html
@@ -619,15 +619,16 @@ <h1>Functions and Closures</h1>
 [py_itertools]: https://docs.python.org/3/library/itertools.html
 [py_json]: https://docs.python.org/3/library/json.html
 [py_jsonschema]: https://python-jsonschema.readthedocs.io/
-[py_metaclass]: https://docs.python.org/3/reference/datamodel.html#metaclasses
 [py_mimetypes]: https://docs.python.org/3/library/mimetypes.html
 [py_pickle]: https://docs.python.org/3/library/pickle.html
 [py_property]: https://docs.python.org/3/library/functions.html#property
 [py_semver]: https://pypi.org/project/semantic-version/
+[py_struct]: https://docs.python.org/3/library/struct.html
 [py_textwrap]: https://docs.python.org/3/library/textwrap.html
 [py_urlparse]: https://docs.python.org/3/library/urllib.parse.html
 [pyfakefs]: https://pytest-pyfakefs.readthedocs.io/
 [pytest]: https://docs.pytest.org/
+[pytest_approx]: https://docs.pytest.org/en/4.6.x/reference.html#pytest-approx
 [python]: https://www.python.org/
 [reim_michael]: https://elderlinux.org/
 [requests]: https://requests.readthedocs.io/
@@ -635,13 +636,15 @@ <h1>Functions and Closures</h1>
 [selenium]: https://www.selenium.dev/
 [semver_spec]: https://semver.org/
 [sinel_joseph]: https://en.wikipedia.org/wiki/Joseph_Claude_Sinel
-[sphinx]: https://www.sphinx-doc.org/
+[snakemake]: https://snakemake.readthedocs.io/
 [sqlite]: https://sqlite.org/
 [stack_connor]: https://connorstack.com/
 [svg_screenshot]: https://chrome.google.com/webstore/detail/svg-screenshot/nfakpcpmhhilkdpphcjgnokknpbpdllg
 [t3_personas]: https://teachtogether.tech/en/index.html#s:process-personas
+[textualize_fraction]: https://www.textualize.io/blog/posts/7-things-about-terminals
 [udhr]: https://www.un.org/en/universal-declaration-human-rights/
 [ungc]: https://www.unglobalcompact.org/what-is-gc/mission/principles
+[unicode]: https://www.unicode.org/
 [unix_glob]: https://en.wikipedia.org/wiki/Glob_(programming)
 [unix_packaging]: https://eerielinux.wordpress.com/2017/08/15/the-history-of-nix-package-management/
 [webaim_wave]: https://wave.webaim.org/
diff --git a/docs/glob/slides/index.html b/docs/glob/slides/index.html
index 44f806f92..0b5727981 100644
--- a/docs/glob/slides/index.html
+++ b/docs/glob/slides/index.html
@@ -4,7 +4,7 @@
   <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
   <meta name="viewport" content="width=device-width, initial-scale=1">
   <meta name="repo" content="https://github.com/gvwilson/sd4ds">
-  <meta name="build_date" content="2023-06-02">
+  <meta name="build_date" content="2023-06-03">
   <meta name="template" content="slides">
   <meta name="major" content="Chapter 3">
   
@@ -525,7 +525,6 @@ <h1>Matching Patterns</h1>
 [lorgat_tutorial]: https://wasimlorgat.com/posts/editor.html
 [lorgat_wasim]: https://wasimlorgat.com/
 [marthas_rules]: https://journals.sagepub.com/doi/10.1177/088610998600100206
-[mkdocs]: https://www.mkdocs.org/
 [nison_mael]: https://arcanis.github.io/
 [nystrom_bob]: http://journal.stuffwithstuff.com/
 [package_manager_tutorial]: https://classic.yarnpkg.com/blog/2017/07/11/lets-dev-a-package-manager/
@@ -540,6 +539,7 @@ <h1>Matching Patterns</h1>
 [py_ast]: https://docs.python.org/3/library/ast.html
 [py_chainmap]: https://docs.python.org/3/library/collections.html#collections.ChainMap
 [py_cprofile]: https://docs.python.org/3/library/profile.html
+[py_fractions]: https://docs.python.org/3/library/fractions.html
 [py_glob]: https://docs.python.org/3/library/glob.html
 [py_hashlib]: https://docs.python.org/3/library/hashlib.html
 [py_inspect]: https://docs.python.org/3/library/inspect.html
@@ -547,15 +547,16 @@ <h1>Matching Patterns</h1>
 [py_itertools]: https://docs.python.org/3/library/itertools.html
 [py_json]: https://docs.python.org/3/library/json.html
 [py_jsonschema]: https://python-jsonschema.readthedocs.io/
-[py_metaclass]: https://docs.python.org/3/reference/datamodel.html#metaclasses
 [py_mimetypes]: https://docs.python.org/3/library/mimetypes.html
 [py_pickle]: https://docs.python.org/3/library/pickle.html
 [py_property]: https://docs.python.org/3/library/functions.html#property
 [py_semver]: https://pypi.org/project/semantic-version/
+[py_struct]: https://docs.python.org/3/library/struct.html
 [py_textwrap]: https://docs.python.org/3/library/textwrap.html
 [py_urlparse]: https://docs.python.org/3/library/urllib.parse.html
 [pyfakefs]: https://pytest-pyfakefs.readthedocs.io/
 [pytest]: https://docs.pytest.org/
+[pytest_approx]: https://docs.pytest.org/en/4.6.x/reference.html#pytest-approx
 [python]: https://www.python.org/
 [reim_michael]: https://elderlinux.org/
 [requests]: https://requests.readthedocs.io/
@@ -563,13 +564,15 @@ <h1>Matching Patterns</h1>
 [selenium]: https://www.selenium.dev/
 [semver_spec]: https://semver.org/
 [sinel_joseph]: https://en.wikipedia.org/wiki/Joseph_Claude_Sinel
-[sphinx]: https://www.sphinx-doc.org/
+[snakemake]: https://snakemake.readthedocs.io/
 [sqlite]: https://sqlite.org/
 [stack_connor]: https://connorstack.com/
 [svg_screenshot]: https://chrome.google.com/webstore/detail/svg-screenshot/nfakpcpmhhilkdpphcjgnokknpbpdllg
 [t3_personas]: https://teachtogether.tech/en/index.html#s:process-personas
+[textualize_fraction]: https://www.textualize.io/blog/posts/7-things-about-terminals
 [udhr]: https://www.un.org/en/universal-declaration-human-rights/
 [ungc]: https://www.unglobalcompact.org/what-is-gc/mission/principles
+[unicode]: https://www.unicode.org/
 [unix_glob]: https://en.wikipedia.org/wiki/Glob_(programming)
 [unix_packaging]: https://eerielinux.wordpress.com/2017/08/15/the-history-of-nix-package-management/
 [webaim_wave]: https://wave.webaim.org/
diff --git a/docs/http/slides/index.html b/docs/http/slides/index.html
index 9225adcd5..28be81517 100644
--- a/docs/http/slides/index.html
+++ b/docs/http/slides/index.html
@@ -4,7 +4,7 @@
   <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
   <meta name="viewport" content="width=device-width, initial-scale=1">
   <meta name="repo" content="https://github.com/gvwilson/sd4ds">
-  <meta name="build_date" content="2023-06-02">
+  <meta name="build_date" content="2023-06-03">
   <meta name="template" content="slides">
   <meta name="major" content="Chapter 22">
   
@@ -257,7 +257,6 @@ <h1>Hello, World!</h1>
 [lorgat_tutorial]: https://wasimlorgat.com/posts/editor.html
 [lorgat_wasim]: https://wasimlorgat.com/
 [marthas_rules]: https://journals.sagepub.com/doi/10.1177/088610998600100206
-[mkdocs]: https://www.mkdocs.org/
 [nison_mael]: https://arcanis.github.io/
 [nystrom_bob]: http://journal.stuffwithstuff.com/
 [package_manager_tutorial]: https://classic.yarnpkg.com/blog/2017/07/11/lets-dev-a-package-manager/
@@ -272,6 +271,7 @@ <h1>Hello, World!</h1>
 [py_ast]: https://docs.python.org/3/library/ast.html
 [py_chainmap]: https://docs.python.org/3/library/collections.html#collections.ChainMap
 [py_cprofile]: https://docs.python.org/3/library/profile.html
+[py_fractions]: https://docs.python.org/3/library/fractions.html
 [py_glob]: https://docs.python.org/3/library/glob.html
 [py_hashlib]: https://docs.python.org/3/library/hashlib.html
 [py_inspect]: https://docs.python.org/3/library/inspect.html
@@ -279,15 +279,16 @@ <h1>Hello, World!</h1>
 [py_itertools]: https://docs.python.org/3/library/itertools.html
 [py_json]: https://docs.python.org/3/library/json.html
 [py_jsonschema]: https://python-jsonschema.readthedocs.io/
-[py_metaclass]: https://docs.python.org/3/reference/datamodel.html#metaclasses
 [py_mimetypes]: https://docs.python.org/3/library/mimetypes.html
 [py_pickle]: https://docs.python.org/3/library/pickle.html
 [py_property]: https://docs.python.org/3/library/functions.html#property
 [py_semver]: https://pypi.org/project/semantic-version/
+[py_struct]: https://docs.python.org/3/library/struct.html
 [py_textwrap]: https://docs.python.org/3/library/textwrap.html
 [py_urlparse]: https://docs.python.org/3/library/urllib.parse.html
 [pyfakefs]: https://pytest-pyfakefs.readthedocs.io/
 [pytest]: https://docs.pytest.org/
+[pytest_approx]: https://docs.pytest.org/en/4.6.x/reference.html#pytest-approx
 [python]: https://www.python.org/
 [reim_michael]: https://elderlinux.org/
 [requests]: https://requests.readthedocs.io/
@@ -295,13 +296,15 @@ <h1>Hello, World!</h1>
 [selenium]: https://www.selenium.dev/
 [semver_spec]: https://semver.org/
 [sinel_joseph]: https://en.wikipedia.org/wiki/Joseph_Claude_Sinel
-[sphinx]: https://www.sphinx-doc.org/
+[snakemake]: https://snakemake.readthedocs.io/
 [sqlite]: https://sqlite.org/
 [stack_connor]: https://connorstack.com/
 [svg_screenshot]: https://chrome.google.com/webstore/detail/svg-screenshot/nfakpcpmhhilkdpphcjgnokknpbpdllg
 [t3_personas]: https://teachtogether.tech/en/index.html#s:process-personas
+[textualize_fraction]: https://www.textualize.io/blog/posts/7-things-about-terminals
 [udhr]: https://www.un.org/en/universal-declaration-human-rights/
 [ungc]: https://www.unglobalcompact.org/what-is-gc/mission/principles
+[unicode]: https://www.unicode.org/
 [unix_glob]: https://en.wikipedia.org/wiki/Glob_(programming)
 [unix_packaging]: https://eerielinux.wordpress.com/2017/08/15/the-history-of-nix-package-management/
 [webaim_wave]: https://wave.webaim.org/
diff --git a/docs/interp/slides/index.html b/docs/interp/slides/index.html
index 98adac23d..366956e65 100644
--- a/docs/interp/slides/index.html
+++ b/docs/interp/slides/index.html
@@ -4,7 +4,7 @@
   <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
   <meta name="viewport" content="width=device-width, initial-scale=1">
   <meta name="repo" content="https://github.com/gvwilson/sd4ds">
-  <meta name="build_date" content="2023-06-02">
+  <meta name="build_date" content="2023-06-03">
   <meta name="template" content="slides">
   <meta name="major" content="Chapter 6">
   
@@ -388,7 +388,6 @@ <h1>An Interpreter</h1>
 [lorgat_tutorial]: https://wasimlorgat.com/posts/editor.html
 [lorgat_wasim]: https://wasimlorgat.com/
 [marthas_rules]: https://journals.sagepub.com/doi/10.1177/088610998600100206
-[mkdocs]: https://www.mkdocs.org/
 [nison_mael]: https://arcanis.github.io/
 [nystrom_bob]: http://journal.stuffwithstuff.com/
 [package_manager_tutorial]: https://classic.yarnpkg.com/blog/2017/07/11/lets-dev-a-package-manager/
@@ -403,6 +402,7 @@ <h1>An Interpreter</h1>
 [py_ast]: https://docs.python.org/3/library/ast.html
 [py_chainmap]: https://docs.python.org/3/library/collections.html#collections.ChainMap
 [py_cprofile]: https://docs.python.org/3/library/profile.html
+[py_fractions]: https://docs.python.org/3/library/fractions.html
 [py_glob]: https://docs.python.org/3/library/glob.html
 [py_hashlib]: https://docs.python.org/3/library/hashlib.html
 [py_inspect]: https://docs.python.org/3/library/inspect.html
@@ -410,15 +410,16 @@ <h1>An Interpreter</h1>
 [py_itertools]: https://docs.python.org/3/library/itertools.html
 [py_json]: https://docs.python.org/3/library/json.html
 [py_jsonschema]: https://python-jsonschema.readthedocs.io/
-[py_metaclass]: https://docs.python.org/3/reference/datamodel.html#metaclasses
 [py_mimetypes]: https://docs.python.org/3/library/mimetypes.html
 [py_pickle]: https://docs.python.org/3/library/pickle.html
 [py_property]: https://docs.python.org/3/library/functions.html#property
 [py_semver]: https://pypi.org/project/semantic-version/
+[py_struct]: https://docs.python.org/3/library/struct.html
 [py_textwrap]: https://docs.python.org/3/library/textwrap.html
 [py_urlparse]: https://docs.python.org/3/library/urllib.parse.html
 [pyfakefs]: https://pytest-pyfakefs.readthedocs.io/
 [pytest]: https://docs.pytest.org/
+[pytest_approx]: https://docs.pytest.org/en/4.6.x/reference.html#pytest-approx
 [python]: https://www.python.org/
 [reim_michael]: https://elderlinux.org/
 [requests]: https://requests.readthedocs.io/
@@ -426,13 +427,15 @@ <h1>An Interpreter</h1>
 [selenium]: https://www.selenium.dev/
 [semver_spec]: https://semver.org/
 [sinel_joseph]: https://en.wikipedia.org/wiki/Joseph_Claude_Sinel
-[sphinx]: https://www.sphinx-doc.org/
+[snakemake]: https://snakemake.readthedocs.io/
 [sqlite]: https://sqlite.org/
 [stack_connor]: https://connorstack.com/
 [svg_screenshot]: https://chrome.google.com/webstore/detail/svg-screenshot/nfakpcpmhhilkdpphcjgnokknpbpdllg
 [t3_personas]: https://teachtogether.tech/en/index.html#s:process-personas
+[textualize_fraction]: https://www.textualize.io/blog/posts/7-things-about-terminals
 [udhr]: https://www.un.org/en/universal-declaration-human-rights/
 [ungc]: https://www.unglobalcompact.org/what-is-gc/mission/principles
+[unicode]: https://www.unicode.org/
 [unix_glob]: https://en.wikipedia.org/wiki/Glob_(programming)
 [unix_packaging]: https://eerielinux.wordpress.com/2017/08/15/the-history-of-nix-package-management/
 [webaim_wave]: https://wave.webaim.org/
diff --git a/docs/intro/slides/index.html b/docs/intro/slides/index.html
index 9113053f7..a324fbe62 100644
--- a/docs/intro/slides/index.html
+++ b/docs/intro/slides/index.html
@@ -4,7 +4,7 @@
   <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
   <meta name="viewport" content="width=device-width, initial-scale=1">
   <meta name="repo" content="https://github.com/gvwilson/sd4ds">
-  <meta name="build_date" content="2023-06-02">
+  <meta name="build_date" content="2023-06-03">
   <meta name="template" content="slides">
   <meta name="major" content="Chapter 1">
   
@@ -169,7 +169,7 @@ <h1>Introduction</h1>
 
 <div class="center">
   <em>
-    This one's for Mike and both Jons:
+    This one's for Mike and Jon:
     <br>
     I'm glad you always found time to chat.
   </em>
@@ -237,7 +237,6 @@ <h1>Introduction</h1>
 [lorgat_tutorial]: https://wasimlorgat.com/posts/editor.html
 [lorgat_wasim]: https://wasimlorgat.com/
 [marthas_rules]: https://journals.sagepub.com/doi/10.1177/088610998600100206
-[mkdocs]: https://www.mkdocs.org/
 [nison_mael]: https://arcanis.github.io/
 [nystrom_bob]: http://journal.stuffwithstuff.com/
 [package_manager_tutorial]: https://classic.yarnpkg.com/blog/2017/07/11/lets-dev-a-package-manager/
@@ -252,6 +251,7 @@ <h1>Introduction</h1>
 [py_ast]: https://docs.python.org/3/library/ast.html
 [py_chainmap]: https://docs.python.org/3/library/collections.html#collections.ChainMap
 [py_cprofile]: https://docs.python.org/3/library/profile.html
+[py_fractions]: https://docs.python.org/3/library/fractions.html
 [py_glob]: https://docs.python.org/3/library/glob.html
 [py_hashlib]: https://docs.python.org/3/library/hashlib.html
 [py_inspect]: https://docs.python.org/3/library/inspect.html
@@ -259,15 +259,16 @@ <h1>Introduction</h1>
 [py_itertools]: https://docs.python.org/3/library/itertools.html
 [py_json]: https://docs.python.org/3/library/json.html
 [py_jsonschema]: https://python-jsonschema.readthedocs.io/
-[py_metaclass]: https://docs.python.org/3/reference/datamodel.html#metaclasses
 [py_mimetypes]: https://docs.python.org/3/library/mimetypes.html
 [py_pickle]: https://docs.python.org/3/library/pickle.html
 [py_property]: https://docs.python.org/3/library/functions.html#property
 [py_semver]: https://pypi.org/project/semantic-version/
+[py_struct]: https://docs.python.org/3/library/struct.html
 [py_textwrap]: https://docs.python.org/3/library/textwrap.html
 [py_urlparse]: https://docs.python.org/3/library/urllib.parse.html
 [pyfakefs]: https://pytest-pyfakefs.readthedocs.io/
 [pytest]: https://docs.pytest.org/
+[pytest_approx]: https://docs.pytest.org/en/4.6.x/reference.html#pytest-approx
 [python]: https://www.python.org/
 [reim_michael]: https://elderlinux.org/
 [requests]: https://requests.readthedocs.io/
@@ -275,13 +276,15 @@ <h1>Introduction</h1>
 [selenium]: https://www.selenium.dev/
 [semver_spec]: https://semver.org/
 [sinel_joseph]: https://en.wikipedia.org/wiki/Joseph_Claude_Sinel
-[sphinx]: https://www.sphinx-doc.org/
+[snakemake]: https://snakemake.readthedocs.io/
 [sqlite]: https://sqlite.org/
 [stack_connor]: https://connorstack.com/
 [svg_screenshot]: https://chrome.google.com/webstore/detail/svg-screenshot/nfakpcpmhhilkdpphcjgnokknpbpdllg
 [t3_personas]: https://teachtogether.tech/en/index.html#s:process-personas
+[textualize_fraction]: https://www.textualize.io/blog/posts/7-things-about-terminals
 [udhr]: https://www.un.org/en/universal-declaration-human-rights/
 [ungc]: https://www.unglobalcompact.org/what-is-gc/mission/principles
+[unicode]: https://www.unicode.org/
 [unix_glob]: https://en.wikipedia.org/wiki/Glob_(programming)
 [unix_packaging]: https://eerielinux.wordpress.com/2017/08/15/the-history-of-nix-package-management/
 [webaim_wave]: https://wave.webaim.org/
diff --git a/docs/layout/slides/index.html b/docs/layout/slides/index.html
index 4804e736b..ccfda12a8 100644
--- a/docs/layout/slides/index.html
+++ b/docs/layout/slides/index.html
@@ -4,7 +4,7 @@
   <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
   <meta name="viewport" content="width=device-width, initial-scale=1">
   <meta name="repo" content="https://github.com/gvwilson/sd4ds">
-  <meta name="build_date" content="2023-06-02">
+  <meta name="build_date" content="2023-06-03">
   <meta name="template" content="slides">
   <meta name="major" content="Chapter 14">
   
@@ -440,7 +440,6 @@ <h1>Page Layout</h1>
 [lorgat_tutorial]: https://wasimlorgat.com/posts/editor.html
 [lorgat_wasim]: https://wasimlorgat.com/
 [marthas_rules]: https://journals.sagepub.com/doi/10.1177/088610998600100206
-[mkdocs]: https://www.mkdocs.org/
 [nison_mael]: https://arcanis.github.io/
 [nystrom_bob]: http://journal.stuffwithstuff.com/
 [package_manager_tutorial]: https://classic.yarnpkg.com/blog/2017/07/11/lets-dev-a-package-manager/
@@ -455,6 +454,7 @@ <h1>Page Layout</h1>
 [py_ast]: https://docs.python.org/3/library/ast.html
 [py_chainmap]: https://docs.python.org/3/library/collections.html#collections.ChainMap
 [py_cprofile]: https://docs.python.org/3/library/profile.html
+[py_fractions]: https://docs.python.org/3/library/fractions.html
 [py_glob]: https://docs.python.org/3/library/glob.html
 [py_hashlib]: https://docs.python.org/3/library/hashlib.html
 [py_inspect]: https://docs.python.org/3/library/inspect.html
@@ -462,15 +462,16 @@ <h1>Page Layout</h1>
 [py_itertools]: https://docs.python.org/3/library/itertools.html
 [py_json]: https://docs.python.org/3/library/json.html
 [py_jsonschema]: https://python-jsonschema.readthedocs.io/
-[py_metaclass]: https://docs.python.org/3/reference/datamodel.html#metaclasses
 [py_mimetypes]: https://docs.python.org/3/library/mimetypes.html
 [py_pickle]: https://docs.python.org/3/library/pickle.html
 [py_property]: https://docs.python.org/3/library/functions.html#property
 [py_semver]: https://pypi.org/project/semantic-version/
+[py_struct]: https://docs.python.org/3/library/struct.html
 [py_textwrap]: https://docs.python.org/3/library/textwrap.html
 [py_urlparse]: https://docs.python.org/3/library/urllib.parse.html
 [pyfakefs]: https://pytest-pyfakefs.readthedocs.io/
 [pytest]: https://docs.pytest.org/
+[pytest_approx]: https://docs.pytest.org/en/4.6.x/reference.html#pytest-approx
 [python]: https://www.python.org/
 [reim_michael]: https://elderlinux.org/
 [requests]: https://requests.readthedocs.io/
@@ -478,13 +479,15 @@ <h1>Page Layout</h1>
 [selenium]: https://www.selenium.dev/
 [semver_spec]: https://semver.org/
 [sinel_joseph]: https://en.wikipedia.org/wiki/Joseph_Claude_Sinel
-[sphinx]: https://www.sphinx-doc.org/
+[snakemake]: https://snakemake.readthedocs.io/
 [sqlite]: https://sqlite.org/
 [stack_connor]: https://connorstack.com/
 [svg_screenshot]: https://chrome.google.com/webstore/detail/svg-screenshot/nfakpcpmhhilkdpphcjgnokknpbpdllg
 [t3_personas]: https://teachtogether.tech/en/index.html#s:process-personas
+[textualize_fraction]: https://www.textualize.io/blog/posts/7-things-about-terminals
 [udhr]: https://www.un.org/en/universal-declaration-human-rights/
 [ungc]: https://www.unglobalcompact.org/what-is-gc/mission/principles
+[unicode]: https://www.unicode.org/
 [unix_glob]: https://en.wikipedia.org/wiki/Glob_(programming)
 [unix_packaging]: https://eerielinux.wordpress.com/2017/08/15/the-history-of-nix-package-management/
 [webaim_wave]: https://wave.webaim.org/
diff --git a/docs/lint/slides/index.html b/docs/lint/slides/index.html
index 2764cda11..584091a6c 100644
--- a/docs/lint/slides/index.html
+++ b/docs/lint/slides/index.html
@@ -4,7 +4,7 @@
   <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
   <meta name="viewport" content="width=device-width, initial-scale=1">
   <meta name="repo" content="https://github.com/gvwilson/sd4ds">
-  <meta name="build_date" content="2023-06-02">
+  <meta name="build_date" content="2023-06-03">
   <meta name="template" content="slides">
   <meta name="major" content="Chapter 13">
   
@@ -501,7 +501,6 @@ <h1>A Code Linter</h1>
 [lorgat_tutorial]: https://wasimlorgat.com/posts/editor.html
 [lorgat_wasim]: https://wasimlorgat.com/
 [marthas_rules]: https://journals.sagepub.com/doi/10.1177/088610998600100206
-[mkdocs]: https://www.mkdocs.org/
 [nison_mael]: https://arcanis.github.io/
 [nystrom_bob]: http://journal.stuffwithstuff.com/
 [package_manager_tutorial]: https://classic.yarnpkg.com/blog/2017/07/11/lets-dev-a-package-manager/
@@ -516,6 +515,7 @@ <h1>A Code Linter</h1>
 [py_ast]: https://docs.python.org/3/library/ast.html
 [py_chainmap]: https://docs.python.org/3/library/collections.html#collections.ChainMap
 [py_cprofile]: https://docs.python.org/3/library/profile.html
+[py_fractions]: https://docs.python.org/3/library/fractions.html
 [py_glob]: https://docs.python.org/3/library/glob.html
 [py_hashlib]: https://docs.python.org/3/library/hashlib.html
 [py_inspect]: https://docs.python.org/3/library/inspect.html
@@ -523,15 +523,16 @@ <h1>A Code Linter</h1>
 [py_itertools]: https://docs.python.org/3/library/itertools.html
 [py_json]: https://docs.python.org/3/library/json.html
 [py_jsonschema]: https://python-jsonschema.readthedocs.io/
-[py_metaclass]: https://docs.python.org/3/reference/datamodel.html#metaclasses
 [py_mimetypes]: https://docs.python.org/3/library/mimetypes.html
 [py_pickle]: https://docs.python.org/3/library/pickle.html
 [py_property]: https://docs.python.org/3/library/functions.html#property
 [py_semver]: https://pypi.org/project/semantic-version/
+[py_struct]: https://docs.python.org/3/library/struct.html
 [py_textwrap]: https://docs.python.org/3/library/textwrap.html
 [py_urlparse]: https://docs.python.org/3/library/urllib.parse.html
 [pyfakefs]: https://pytest-pyfakefs.readthedocs.io/
 [pytest]: https://docs.pytest.org/
+[pytest_approx]: https://docs.pytest.org/en/4.6.x/reference.html#pytest-approx
 [python]: https://www.python.org/
 [reim_michael]: https://elderlinux.org/
 [requests]: https://requests.readthedocs.io/
@@ -539,13 +540,15 @@ <h1>A Code Linter</h1>
 [selenium]: https://www.selenium.dev/
 [semver_spec]: https://semver.org/
 [sinel_joseph]: https://en.wikipedia.org/wiki/Joseph_Claude_Sinel
-[sphinx]: https://www.sphinx-doc.org/
+[snakemake]: https://snakemake.readthedocs.io/
 [sqlite]: https://sqlite.org/
 [stack_connor]: https://connorstack.com/
 [svg_screenshot]: https://chrome.google.com/webstore/detail/svg-screenshot/nfakpcpmhhilkdpphcjgnokknpbpdllg
 [t3_personas]: https://teachtogether.tech/en/index.html#s:process-personas
+[textualize_fraction]: https://www.textualize.io/blog/posts/7-things-about-terminals
 [udhr]: https://www.un.org/en/universal-declaration-human-rights/
 [ungc]: https://www.unglobalcompact.org/what-is-gc/mission/principles
+[unicode]: https://www.unicode.org/
 [unix_glob]: https://en.wikipedia.org/wiki/Glob_(programming)
 [unix_packaging]: https://eerielinux.wordpress.com/2017/08/15/the-history-of-nix-package-management/
 [webaim_wave]: https://wave.webaim.org/
diff --git a/docs/mock/slides/index.html b/docs/mock/slides/index.html
index ae9921eec..d3aacc3ff 100644
--- a/docs/mock/slides/index.html
+++ b/docs/mock/slides/index.html
@@ -4,7 +4,7 @@
   <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
   <meta name="viewport" content="width=device-width, initial-scale=1">
   <meta name="repo" content="https://github.com/gvwilson/sd4ds">
-  <meta name="build_date" content="2023-06-02">
+  <meta name="build_date" content="2023-06-03">
   <meta name="template" content="slides">
   <meta name="major" content="Chapter 8">
   
@@ -95,7 +95,6 @@ <h1>Mock Objects</h1>
 [lorgat_tutorial]: https://wasimlorgat.com/posts/editor.html
 [lorgat_wasim]: https://wasimlorgat.com/
 [marthas_rules]: https://journals.sagepub.com/doi/10.1177/088610998600100206
-[mkdocs]: https://www.mkdocs.org/
 [nison_mael]: https://arcanis.github.io/
 [nystrom_bob]: http://journal.stuffwithstuff.com/
 [package_manager_tutorial]: https://classic.yarnpkg.com/blog/2017/07/11/lets-dev-a-package-manager/
@@ -110,6 +109,7 @@ <h1>Mock Objects</h1>
 [py_ast]: https://docs.python.org/3/library/ast.html
 [py_chainmap]: https://docs.python.org/3/library/collections.html#collections.ChainMap
 [py_cprofile]: https://docs.python.org/3/library/profile.html
+[py_fractions]: https://docs.python.org/3/library/fractions.html
 [py_glob]: https://docs.python.org/3/library/glob.html
 [py_hashlib]: https://docs.python.org/3/library/hashlib.html
 [py_inspect]: https://docs.python.org/3/library/inspect.html
@@ -117,15 +117,16 @@ <h1>Mock Objects</h1>
 [py_itertools]: https://docs.python.org/3/library/itertools.html
 [py_json]: https://docs.python.org/3/library/json.html
 [py_jsonschema]: https://python-jsonschema.readthedocs.io/
-[py_metaclass]: https://docs.python.org/3/reference/datamodel.html#metaclasses
 [py_mimetypes]: https://docs.python.org/3/library/mimetypes.html
 [py_pickle]: https://docs.python.org/3/library/pickle.html
 [py_property]: https://docs.python.org/3/library/functions.html#property
 [py_semver]: https://pypi.org/project/semantic-version/
+[py_struct]: https://docs.python.org/3/library/struct.html
 [py_textwrap]: https://docs.python.org/3/library/textwrap.html
 [py_urlparse]: https://docs.python.org/3/library/urllib.parse.html
 [pyfakefs]: https://pytest-pyfakefs.readthedocs.io/
 [pytest]: https://docs.pytest.org/
+[pytest_approx]: https://docs.pytest.org/en/4.6.x/reference.html#pytest-approx
 [python]: https://www.python.org/
 [reim_michael]: https://elderlinux.org/
 [requests]: https://requests.readthedocs.io/
@@ -133,13 +134,15 @@ <h1>Mock Objects</h1>
 [selenium]: https://www.selenium.dev/
 [semver_spec]: https://semver.org/
 [sinel_joseph]: https://en.wikipedia.org/wiki/Joseph_Claude_Sinel
-[sphinx]: https://www.sphinx-doc.org/
+[snakemake]: https://snakemake.readthedocs.io/
 [sqlite]: https://sqlite.org/
 [stack_connor]: https://connorstack.com/
 [svg_screenshot]: https://chrome.google.com/webstore/detail/svg-screenshot/nfakpcpmhhilkdpphcjgnokknpbpdllg
 [t3_personas]: https://teachtogether.tech/en/index.html#s:process-personas
+[textualize_fraction]: https://www.textualize.io/blog/posts/7-things-about-terminals
 [udhr]: https://www.un.org/en/universal-declaration-human-rights/
 [ungc]: https://www.unglobalcompact.org/what-is-gc/mission/principles
+[unicode]: https://www.unicode.org/
 [unix_glob]: https://en.wikipedia.org/wiki/Glob_(programming)
 [unix_packaging]: https://eerielinux.wordpress.com/2017/08/15/the-history-of-nix-package-management/
 [webaim_wave]: https://wave.webaim.org/
diff --git a/docs/oop/slides/index.html b/docs/oop/slides/index.html
index 6de14566c..22db23ff1 100644
--- a/docs/oop/slides/index.html
+++ b/docs/oop/slides/index.html
@@ -4,7 +4,7 @@
   <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
   <meta name="viewport" content="width=device-width, initial-scale=1">
   <meta name="repo" content="https://github.com/gvwilson/sd4ds">
-  <meta name="build_date" content="2023-06-02">
+  <meta name="build_date" content="2023-06-03">
   <meta name="template" content="slides">
   <meta name="major" content="Chapter 10">
   
@@ -477,7 +477,6 @@ <h1>Objects and Classes</h1>
 [lorgat_tutorial]: https://wasimlorgat.com/posts/editor.html
 [lorgat_wasim]: https://wasimlorgat.com/
 [marthas_rules]: https://journals.sagepub.com/doi/10.1177/088610998600100206
-[mkdocs]: https://www.mkdocs.org/
 [nison_mael]: https://arcanis.github.io/
 [nystrom_bob]: http://journal.stuffwithstuff.com/
 [package_manager_tutorial]: https://classic.yarnpkg.com/blog/2017/07/11/lets-dev-a-package-manager/
@@ -492,6 +491,7 @@ <h1>Objects and Classes</h1>
 [py_ast]: https://docs.python.org/3/library/ast.html
 [py_chainmap]: https://docs.python.org/3/library/collections.html#collections.ChainMap
 [py_cprofile]: https://docs.python.org/3/library/profile.html
+[py_fractions]: https://docs.python.org/3/library/fractions.html
 [py_glob]: https://docs.python.org/3/library/glob.html
 [py_hashlib]: https://docs.python.org/3/library/hashlib.html
 [py_inspect]: https://docs.python.org/3/library/inspect.html
@@ -499,15 +499,16 @@ <h1>Objects and Classes</h1>
 [py_itertools]: https://docs.python.org/3/library/itertools.html
 [py_json]: https://docs.python.org/3/library/json.html
 [py_jsonschema]: https://python-jsonschema.readthedocs.io/
-[py_metaclass]: https://docs.python.org/3/reference/datamodel.html#metaclasses
 [py_mimetypes]: https://docs.python.org/3/library/mimetypes.html
 [py_pickle]: https://docs.python.org/3/library/pickle.html
 [py_property]: https://docs.python.org/3/library/functions.html#property
 [py_semver]: https://pypi.org/project/semantic-version/
+[py_struct]: https://docs.python.org/3/library/struct.html
 [py_textwrap]: https://docs.python.org/3/library/textwrap.html
 [py_urlparse]: https://docs.python.org/3/library/urllib.parse.html
 [pyfakefs]: https://pytest-pyfakefs.readthedocs.io/
 [pytest]: https://docs.pytest.org/
+[pytest_approx]: https://docs.pytest.org/en/4.6.x/reference.html#pytest-approx
 [python]: https://www.python.org/
 [reim_michael]: https://elderlinux.org/
 [requests]: https://requests.readthedocs.io/
@@ -515,13 +516,15 @@ <h1>Objects and Classes</h1>
 [selenium]: https://www.selenium.dev/
 [semver_spec]: https://semver.org/
 [sinel_joseph]: https://en.wikipedia.org/wiki/Joseph_Claude_Sinel
-[sphinx]: https://www.sphinx-doc.org/
+[snakemake]: https://snakemake.readthedocs.io/
 [sqlite]: https://sqlite.org/
 [stack_connor]: https://connorstack.com/
 [svg_screenshot]: https://chrome.google.com/webstore/detail/svg-screenshot/nfakpcpmhhilkdpphcjgnokknpbpdllg
 [t3_personas]: https://teachtogether.tech/en/index.html#s:process-personas
+[textualize_fraction]: https://www.textualize.io/blog/posts/7-things-about-terminals
 [udhr]: https://www.un.org/en/universal-declaration-human-rights/
 [ungc]: https://www.unglobalcompact.org/what-is-gc/mission/principles
+[unicode]: https://www.unicode.org/
 [unix_glob]: https://en.wikipedia.org/wiki/Glob_(programming)
 [unix_packaging]: https://eerielinux.wordpress.com/2017/08/15/the-history-of-nix-package-management/
 [webaim_wave]: https://wave.webaim.org/
diff --git a/docs/pack/index.html b/docs/pack/index.html
index d15ba479b..1deba70db 100644
--- a/docs/pack/index.html
+++ b/docs/pack/index.html
@@ -4,7 +4,7 @@
   <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
   <meta name="viewport" content="width=device-width, initial-scale=1">
   <meta name="repo" content="https://github.com/gvwilson/sd4ds">
-  <meta name="build_date" content="2023-06-02">
+  <meta name="build_date" content="2023-06-03">
   <meta name="template" content="default">
   <meta name="major" content="Chapter 20">
   <meta name="has_slides" content="true">
@@ -602,6 +602,14 @@ <h2 id="pack-manual">Section 20.3: Generating Possibilities Manually</h2>
             <span class="n">_make_possible</span><span class="p">(</span><span class="n">tail</span><span class="p">,</span> <span class="n">current</span> <span class="o">+</span> <span class="p">[</span><span class="n">h</span><span class="p">],</span> <span class="n">accum</span><span class="p">)</span>
 </code></pre></div>
 </div>
+<div class="code-sample lang-out" title="manual.out">
+<div class="highlight"><pre><span></span><code>18 possibilities
+3 allowed
+[(&#39;A&#39;, &#39;3&#39;), (&#39;B&#39;, &#39;3&#39;), (&#39;C&#39;, &#39;2&#39;)]
+[(&#39;A&#39;, &#39;2&#39;), (&#39;B&#39;, &#39;2&#39;), (&#39;C&#39;, &#39;1&#39;)]
+[(&#39;A&#39;, &#39;1&#39;), (&#39;B&#39;, &#39;1&#39;), (&#39;C&#39;, &#39;1&#39;)]
+</code></pre></div>
+</div>
 <figure id="pack-recursive">
 <img src="./recursive.svg" alt="Generating a cross-product recursively"/>
 <figcaption markdown="1">Figure 20.3: Generating all possible combinations of items recursively.</figcaption>
diff --git a/docs/pack/slides/index.html b/docs/pack/slides/index.html
index f3ef775fa..1ff5f594a 100644
--- a/docs/pack/slides/index.html
+++ b/docs/pack/slides/index.html
@@ -4,7 +4,7 @@
   <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
   <meta name="viewport" content="width=device-width, initial-scale=1">
   <meta name="repo" content="https://github.com/gvwilson/sd4ds">
-  <meta name="build_date" content="2023-06-02">
+  <meta name="build_date" content="2023-06-03">
   <meta name="template" content="slides">
   <meta name="major" content="Chapter 20">
   
@@ -584,7 +584,6 @@ <h1>A Package Manager</h1>
 [lorgat_tutorial]: https://wasimlorgat.com/posts/editor.html
 [lorgat_wasim]: https://wasimlorgat.com/
 [marthas_rules]: https://journals.sagepub.com/doi/10.1177/088610998600100206
-[mkdocs]: https://www.mkdocs.org/
 [nison_mael]: https://arcanis.github.io/
 [nystrom_bob]: http://journal.stuffwithstuff.com/
 [package_manager_tutorial]: https://classic.yarnpkg.com/blog/2017/07/11/lets-dev-a-package-manager/
@@ -599,6 +598,7 @@ <h1>A Package Manager</h1>
 [py_ast]: https://docs.python.org/3/library/ast.html
 [py_chainmap]: https://docs.python.org/3/library/collections.html#collections.ChainMap
 [py_cprofile]: https://docs.python.org/3/library/profile.html
+[py_fractions]: https://docs.python.org/3/library/fractions.html
 [py_glob]: https://docs.python.org/3/library/glob.html
 [py_hashlib]: https://docs.python.org/3/library/hashlib.html
 [py_inspect]: https://docs.python.org/3/library/inspect.html
@@ -606,15 +606,16 @@ <h1>A Package Manager</h1>
 [py_itertools]: https://docs.python.org/3/library/itertools.html
 [py_json]: https://docs.python.org/3/library/json.html
 [py_jsonschema]: https://python-jsonschema.readthedocs.io/
-[py_metaclass]: https://docs.python.org/3/reference/datamodel.html#metaclasses
 [py_mimetypes]: https://docs.python.org/3/library/mimetypes.html
 [py_pickle]: https://docs.python.org/3/library/pickle.html
 [py_property]: https://docs.python.org/3/library/functions.html#property
 [py_semver]: https://pypi.org/project/semantic-version/
+[py_struct]: https://docs.python.org/3/library/struct.html
 [py_textwrap]: https://docs.python.org/3/library/textwrap.html
 [py_urlparse]: https://docs.python.org/3/library/urllib.parse.html
 [pyfakefs]: https://pytest-pyfakefs.readthedocs.io/
 [pytest]: https://docs.pytest.org/
+[pytest_approx]: https://docs.pytest.org/en/4.6.x/reference.html#pytest-approx
 [python]: https://www.python.org/
 [reim_michael]: https://elderlinux.org/
 [requests]: https://requests.readthedocs.io/
@@ -622,13 +623,15 @@ <h1>A Package Manager</h1>
 [selenium]: https://www.selenium.dev/
 [semver_spec]: https://semver.org/
 [sinel_joseph]: https://en.wikipedia.org/wiki/Joseph_Claude_Sinel
-[sphinx]: https://www.sphinx-doc.org/
+[snakemake]: https://snakemake.readthedocs.io/
 [sqlite]: https://sqlite.org/
 [stack_connor]: https://connorstack.com/
 [svg_screenshot]: https://chrome.google.com/webstore/detail/svg-screenshot/nfakpcpmhhilkdpphcjgnokknpbpdllg
 [t3_personas]: https://teachtogether.tech/en/index.html#s:process-personas
+[textualize_fraction]: https://www.textualize.io/blog/posts/7-things-about-terminals
 [udhr]: https://www.un.org/en/universal-declaration-human-rights/
 [ungc]: https://www.unglobalcompact.org/what-is-gc/mission/principles
+[unicode]: https://www.unicode.org/
 [unix_glob]: https://en.wikipedia.org/wiki/Glob_(programming)
 [unix_packaging]: https://eerielinux.wordpress.com/2017/08/15/the-history-of-nix-package-management/
 [webaim_wave]: https://wave.webaim.org/
diff --git a/docs/parse/slides/index.html b/docs/parse/slides/index.html
index 368023f07..74a921eca 100644
--- a/docs/parse/slides/index.html
+++ b/docs/parse/slides/index.html
@@ -4,7 +4,7 @@
   <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
   <meta name="viewport" content="width=device-width, initial-scale=1">
   <meta name="repo" content="https://github.com/gvwilson/sd4ds">
-  <meta name="build_date" content="2023-06-02">
+  <meta name="build_date" content="2023-06-03">
   <meta name="template" content="slides">
   <meta name="major" content="Chapter 4">
   
@@ -393,7 +393,6 @@ <h1>Parsing Text</h1>
 [lorgat_tutorial]: https://wasimlorgat.com/posts/editor.html
 [lorgat_wasim]: https://wasimlorgat.com/
 [marthas_rules]: https://journals.sagepub.com/doi/10.1177/088610998600100206
-[mkdocs]: https://www.mkdocs.org/
 [nison_mael]: https://arcanis.github.io/
 [nystrom_bob]: http://journal.stuffwithstuff.com/
 [package_manager_tutorial]: https://classic.yarnpkg.com/blog/2017/07/11/lets-dev-a-package-manager/
@@ -408,6 +407,7 @@ <h1>Parsing Text</h1>
 [py_ast]: https://docs.python.org/3/library/ast.html
 [py_chainmap]: https://docs.python.org/3/library/collections.html#collections.ChainMap
 [py_cprofile]: https://docs.python.org/3/library/profile.html
+[py_fractions]: https://docs.python.org/3/library/fractions.html
 [py_glob]: https://docs.python.org/3/library/glob.html
 [py_hashlib]: https://docs.python.org/3/library/hashlib.html
 [py_inspect]: https://docs.python.org/3/library/inspect.html
@@ -415,15 +415,16 @@ <h1>Parsing Text</h1>
 [py_itertools]: https://docs.python.org/3/library/itertools.html
 [py_json]: https://docs.python.org/3/library/json.html
 [py_jsonschema]: https://python-jsonschema.readthedocs.io/
-[py_metaclass]: https://docs.python.org/3/reference/datamodel.html#metaclasses
 [py_mimetypes]: https://docs.python.org/3/library/mimetypes.html
 [py_pickle]: https://docs.python.org/3/library/pickle.html
 [py_property]: https://docs.python.org/3/library/functions.html#property
 [py_semver]: https://pypi.org/project/semantic-version/
+[py_struct]: https://docs.python.org/3/library/struct.html
 [py_textwrap]: https://docs.python.org/3/library/textwrap.html
 [py_urlparse]: https://docs.python.org/3/library/urllib.parse.html
 [pyfakefs]: https://pytest-pyfakefs.readthedocs.io/
 [pytest]: https://docs.pytest.org/
+[pytest_approx]: https://docs.pytest.org/en/4.6.x/reference.html#pytest-approx
 [python]: https://www.python.org/
 [reim_michael]: https://elderlinux.org/
 [requests]: https://requests.readthedocs.io/
@@ -431,13 +432,15 @@ <h1>Parsing Text</h1>
 [selenium]: https://www.selenium.dev/
 [semver_spec]: https://semver.org/
 [sinel_joseph]: https://en.wikipedia.org/wiki/Joseph_Claude_Sinel
-[sphinx]: https://www.sphinx-doc.org/
+[snakemake]: https://snakemake.readthedocs.io/
 [sqlite]: https://sqlite.org/
 [stack_connor]: https://connorstack.com/
 [svg_screenshot]: https://chrome.google.com/webstore/detail/svg-screenshot/nfakpcpmhhilkdpphcjgnokknpbpdllg
 [t3_personas]: https://teachtogether.tech/en/index.html#s:process-personas
+[textualize_fraction]: https://www.textualize.io/blog/posts/7-things-about-terminals
 [udhr]: https://www.un.org/en/universal-declaration-human-rights/
 [ungc]: https://www.unglobalcompact.org/what-is-gc/mission/principles
+[unicode]: https://www.unicode.org/
 [unix_glob]: https://en.wikipedia.org/wiki/Glob_(programming)
 [unix_packaging]: https://eerielinux.wordpress.com/2017/08/15/the-history-of-nix-package-management/
 [webaim_wave]: https://wave.webaim.org/
diff --git a/docs/perf/slides/index.html b/docs/perf/slides/index.html
index a34bb158b..09fa14503 100644
--- a/docs/perf/slides/index.html
+++ b/docs/perf/slides/index.html
@@ -4,7 +4,7 @@
   <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
   <meta name="viewport" content="width=device-width, initial-scale=1">
   <meta name="repo" content="https://github.com/gvwilson/sd4ds">
-  <meta name="build_date" content="2023-06-02">
+  <meta name="build_date" content="2023-06-03">
   <meta name="template" content="slides">
   <meta name="major" content="Chapter 15">
   
@@ -556,7 +556,6 @@ <h1>Performance Profiling</h1>
 [lorgat_tutorial]: https://wasimlorgat.com/posts/editor.html
 [lorgat_wasim]: https://wasimlorgat.com/
 [marthas_rules]: https://journals.sagepub.com/doi/10.1177/088610998600100206
-[mkdocs]: https://www.mkdocs.org/
 [nison_mael]: https://arcanis.github.io/
 [nystrom_bob]: http://journal.stuffwithstuff.com/
 [package_manager_tutorial]: https://classic.yarnpkg.com/blog/2017/07/11/lets-dev-a-package-manager/
@@ -571,6 +570,7 @@ <h1>Performance Profiling</h1>
 [py_ast]: https://docs.python.org/3/library/ast.html
 [py_chainmap]: https://docs.python.org/3/library/collections.html#collections.ChainMap
 [py_cprofile]: https://docs.python.org/3/library/profile.html
+[py_fractions]: https://docs.python.org/3/library/fractions.html
 [py_glob]: https://docs.python.org/3/library/glob.html
 [py_hashlib]: https://docs.python.org/3/library/hashlib.html
 [py_inspect]: https://docs.python.org/3/library/inspect.html
@@ -578,15 +578,16 @@ <h1>Performance Profiling</h1>
 [py_itertools]: https://docs.python.org/3/library/itertools.html
 [py_json]: https://docs.python.org/3/library/json.html
 [py_jsonschema]: https://python-jsonschema.readthedocs.io/
-[py_metaclass]: https://docs.python.org/3/reference/datamodel.html#metaclasses
 [py_mimetypes]: https://docs.python.org/3/library/mimetypes.html
 [py_pickle]: https://docs.python.org/3/library/pickle.html
 [py_property]: https://docs.python.org/3/library/functions.html#property
 [py_semver]: https://pypi.org/project/semantic-version/
+[py_struct]: https://docs.python.org/3/library/struct.html
 [py_textwrap]: https://docs.python.org/3/library/textwrap.html
 [py_urlparse]: https://docs.python.org/3/library/urllib.parse.html
 [pyfakefs]: https://pytest-pyfakefs.readthedocs.io/
 [pytest]: https://docs.pytest.org/
+[pytest_approx]: https://docs.pytest.org/en/4.6.x/reference.html#pytest-approx
 [python]: https://www.python.org/
 [reim_michael]: https://elderlinux.org/
 [requests]: https://requests.readthedocs.io/
@@ -594,13 +595,15 @@ <h1>Performance Profiling</h1>
 [selenium]: https://www.selenium.dev/
 [semver_spec]: https://semver.org/
 [sinel_joseph]: https://en.wikipedia.org/wiki/Joseph_Claude_Sinel
-[sphinx]: https://www.sphinx-doc.org/
+[snakemake]: https://snakemake.readthedocs.io/
 [sqlite]: https://sqlite.org/
 [stack_connor]: https://connorstack.com/
 [svg_screenshot]: https://chrome.google.com/webstore/detail/svg-screenshot/nfakpcpmhhilkdpphcjgnokknpbpdllg
 [t3_personas]: https://teachtogether.tech/en/index.html#s:process-personas
+[textualize_fraction]: https://www.textualize.io/blog/posts/7-things-about-terminals
 [udhr]: https://www.un.org/en/universal-declaration-human-rights/
 [ungc]: https://www.unglobalcompact.org/what-is-gc/mission/principles
+[unicode]: https://www.unicode.org/
 [unix_glob]: https://en.wikipedia.org/wiki/Glob_(programming)
 [unix_packaging]: https://eerielinux.wordpress.com/2017/08/15/the-history-of-nix-package-management/
 [webaim_wave]: https://wave.webaim.org/
diff --git a/docs/persist/slides/index.html b/docs/persist/slides/index.html
index bf228ab93..e162fce1f 100644
--- a/docs/persist/slides/index.html
+++ b/docs/persist/slides/index.html
@@ -4,7 +4,7 @@
   <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
   <meta name="viewport" content="width=device-width, initial-scale=1">
   <meta name="repo" content="https://github.com/gvwilson/sd4ds">
-  <meta name="build_date" content="2023-06-02">
+  <meta name="build_date" content="2023-06-03">
   <meta name="template" content="slides">
   <meta name="major" content="Chapter 16">
   
@@ -381,7 +381,6 @@ <h1>Object Persistence</h1>
 [lorgat_tutorial]: https://wasimlorgat.com/posts/editor.html
 [lorgat_wasim]: https://wasimlorgat.com/
 [marthas_rules]: https://journals.sagepub.com/doi/10.1177/088610998600100206
-[mkdocs]: https://www.mkdocs.org/
 [nison_mael]: https://arcanis.github.io/
 [nystrom_bob]: http://journal.stuffwithstuff.com/
 [package_manager_tutorial]: https://classic.yarnpkg.com/blog/2017/07/11/lets-dev-a-package-manager/
@@ -396,6 +395,7 @@ <h1>Object Persistence</h1>
 [py_ast]: https://docs.python.org/3/library/ast.html
 [py_chainmap]: https://docs.python.org/3/library/collections.html#collections.ChainMap
 [py_cprofile]: https://docs.python.org/3/library/profile.html
+[py_fractions]: https://docs.python.org/3/library/fractions.html
 [py_glob]: https://docs.python.org/3/library/glob.html
 [py_hashlib]: https://docs.python.org/3/library/hashlib.html
 [py_inspect]: https://docs.python.org/3/library/inspect.html
@@ -403,15 +403,16 @@ <h1>Object Persistence</h1>
 [py_itertools]: https://docs.python.org/3/library/itertools.html
 [py_json]: https://docs.python.org/3/library/json.html
 [py_jsonschema]: https://python-jsonschema.readthedocs.io/
-[py_metaclass]: https://docs.python.org/3/reference/datamodel.html#metaclasses
 [py_mimetypes]: https://docs.python.org/3/library/mimetypes.html
 [py_pickle]: https://docs.python.org/3/library/pickle.html
 [py_property]: https://docs.python.org/3/library/functions.html#property
 [py_semver]: https://pypi.org/project/semantic-version/
+[py_struct]: https://docs.python.org/3/library/struct.html
 [py_textwrap]: https://docs.python.org/3/library/textwrap.html
 [py_urlparse]: https://docs.python.org/3/library/urllib.parse.html
 [pyfakefs]: https://pytest-pyfakefs.readthedocs.io/
 [pytest]: https://docs.pytest.org/
+[pytest_approx]: https://docs.pytest.org/en/4.6.x/reference.html#pytest-approx
 [python]: https://www.python.org/
 [reim_michael]: https://elderlinux.org/
 [requests]: https://requests.readthedocs.io/
@@ -419,13 +420,15 @@ <h1>Object Persistence</h1>
 [selenium]: https://www.selenium.dev/
 [semver_spec]: https://semver.org/
 [sinel_joseph]: https://en.wikipedia.org/wiki/Joseph_Claude_Sinel
-[sphinx]: https://www.sphinx-doc.org/
+[snakemake]: https://snakemake.readthedocs.io/
 [sqlite]: https://sqlite.org/
 [stack_connor]: https://connorstack.com/
 [svg_screenshot]: https://chrome.google.com/webstore/detail/svg-screenshot/nfakpcpmhhilkdpphcjgnokknpbpdllg
 [t3_personas]: https://teachtogether.tech/en/index.html#s:process-personas
+[textualize_fraction]: https://www.textualize.io/blog/posts/7-things-about-terminals
 [udhr]: https://www.un.org/en/universal-declaration-human-rights/
 [ungc]: https://www.unglobalcompact.org/what-is-gc/mission/principles
+[unicode]: https://www.unicode.org/
 [unix_glob]: https://en.wikipedia.org/wiki/Glob_(programming)
 [unix_packaging]: https://eerielinux.wordpress.com/2017/08/15/the-history-of-nix-package-management/
 [webaim_wave]: https://wave.webaim.org/
diff --git a/docs/template/slides/index.html b/docs/template/slides/index.html
index f53150478..0b8e5152b 100644
--- a/docs/template/slides/index.html
+++ b/docs/template/slides/index.html
@@ -4,7 +4,7 @@
   <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
   <meta name="viewport" content="width=device-width, initial-scale=1">
   <meta name="repo" content="https://github.com/gvwilson/sd4ds">
-  <meta name="build_date" content="2023-06-02">
+  <meta name="build_date" content="2023-06-03">
   <meta name="template" content="slides">
   <meta name="major" content="Chapter 12">
   
@@ -597,7 +597,6 @@ <h1>Static Text</h1>
 [lorgat_tutorial]: https://wasimlorgat.com/posts/editor.html
 [lorgat_wasim]: https://wasimlorgat.com/
 [marthas_rules]: https://journals.sagepub.com/doi/10.1177/088610998600100206
-[mkdocs]: https://www.mkdocs.org/
 [nison_mael]: https://arcanis.github.io/
 [nystrom_bob]: http://journal.stuffwithstuff.com/
 [package_manager_tutorial]: https://classic.yarnpkg.com/blog/2017/07/11/lets-dev-a-package-manager/
@@ -612,6 +611,7 @@ <h1>Static Text</h1>
 [py_ast]: https://docs.python.org/3/library/ast.html
 [py_chainmap]: https://docs.python.org/3/library/collections.html#collections.ChainMap
 [py_cprofile]: https://docs.python.org/3/library/profile.html
+[py_fractions]: https://docs.python.org/3/library/fractions.html
 [py_glob]: https://docs.python.org/3/library/glob.html
 [py_hashlib]: https://docs.python.org/3/library/hashlib.html
 [py_inspect]: https://docs.python.org/3/library/inspect.html
@@ -619,15 +619,16 @@ <h1>Static Text</h1>
 [py_itertools]: https://docs.python.org/3/library/itertools.html
 [py_json]: https://docs.python.org/3/library/json.html
 [py_jsonschema]: https://python-jsonschema.readthedocs.io/
-[py_metaclass]: https://docs.python.org/3/reference/datamodel.html#metaclasses
 [py_mimetypes]: https://docs.python.org/3/library/mimetypes.html
 [py_pickle]: https://docs.python.org/3/library/pickle.html
 [py_property]: https://docs.python.org/3/library/functions.html#property
 [py_semver]: https://pypi.org/project/semantic-version/
+[py_struct]: https://docs.python.org/3/library/struct.html
 [py_textwrap]: https://docs.python.org/3/library/textwrap.html
 [py_urlparse]: https://docs.python.org/3/library/urllib.parse.html
 [pyfakefs]: https://pytest-pyfakefs.readthedocs.io/
 [pytest]: https://docs.pytest.org/
+[pytest_approx]: https://docs.pytest.org/en/4.6.x/reference.html#pytest-approx
 [python]: https://www.python.org/
 [reim_michael]: https://elderlinux.org/
 [requests]: https://requests.readthedocs.io/
@@ -635,13 +636,15 @@ <h1>Static Text</h1>
 [selenium]: https://www.selenium.dev/
 [semver_spec]: https://semver.org/
 [sinel_joseph]: https://en.wikipedia.org/wiki/Joseph_Claude_Sinel
-[sphinx]: https://www.sphinx-doc.org/
+[snakemake]: https://snakemake.readthedocs.io/
 [sqlite]: https://sqlite.org/
 [stack_connor]: https://connorstack.com/
 [svg_screenshot]: https://chrome.google.com/webstore/detail/svg-screenshot/nfakpcpmhhilkdpphcjgnokknpbpdllg
 [t3_personas]: https://teachtogether.tech/en/index.html#s:process-personas
+[textualize_fraction]: https://www.textualize.io/blog/posts/7-things-about-terminals
 [udhr]: https://www.un.org/en/universal-declaration-human-rights/
 [ungc]: https://www.unglobalcompact.org/what-is-gc/mission/principles
+[unicode]: https://www.unicode.org/
 [unix_glob]: https://en.wikipedia.org/wiki/Glob_(programming)
 [unix_packaging]: https://eerielinux.wordpress.com/2017/08/15/the-history-of-nix-package-management/
 [webaim_wave]: https://wave.webaim.org/
diff --git a/docs/test/slides/index.html b/docs/test/slides/index.html
index 0be538a61..1e54befc9 100644
--- a/docs/test/slides/index.html
+++ b/docs/test/slides/index.html
@@ -4,7 +4,7 @@
   <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
   <meta name="viewport" content="width=device-width, initial-scale=1">
   <meta name="repo" content="https://github.com/gvwilson/sd4ds">
-  <meta name="build_date" content="2023-06-02">
+  <meta name="build_date" content="2023-06-03">
   <meta name="template" content="slides">
   <meta name="major" content="Chapter 5">
   
@@ -492,7 +492,6 @@ <h1>A Test Runner</h1>
 [lorgat_tutorial]: https://wasimlorgat.com/posts/editor.html
 [lorgat_wasim]: https://wasimlorgat.com/
 [marthas_rules]: https://journals.sagepub.com/doi/10.1177/088610998600100206
-[mkdocs]: https://www.mkdocs.org/
 [nison_mael]: https://arcanis.github.io/
 [nystrom_bob]: http://journal.stuffwithstuff.com/
 [package_manager_tutorial]: https://classic.yarnpkg.com/blog/2017/07/11/lets-dev-a-package-manager/
@@ -507,6 +506,7 @@ <h1>A Test Runner</h1>
 [py_ast]: https://docs.python.org/3/library/ast.html
 [py_chainmap]: https://docs.python.org/3/library/collections.html#collections.ChainMap
 [py_cprofile]: https://docs.python.org/3/library/profile.html
+[py_fractions]: https://docs.python.org/3/library/fractions.html
 [py_glob]: https://docs.python.org/3/library/glob.html
 [py_hashlib]: https://docs.python.org/3/library/hashlib.html
 [py_inspect]: https://docs.python.org/3/library/inspect.html
@@ -514,15 +514,16 @@ <h1>A Test Runner</h1>
 [py_itertools]: https://docs.python.org/3/library/itertools.html
 [py_json]: https://docs.python.org/3/library/json.html
 [py_jsonschema]: https://python-jsonschema.readthedocs.io/
-[py_metaclass]: https://docs.python.org/3/reference/datamodel.html#metaclasses
 [py_mimetypes]: https://docs.python.org/3/library/mimetypes.html
 [py_pickle]: https://docs.python.org/3/library/pickle.html
 [py_property]: https://docs.python.org/3/library/functions.html#property
 [py_semver]: https://pypi.org/project/semantic-version/
+[py_struct]: https://docs.python.org/3/library/struct.html
 [py_textwrap]: https://docs.python.org/3/library/textwrap.html
 [py_urlparse]: https://docs.python.org/3/library/urllib.parse.html
 [pyfakefs]: https://pytest-pyfakefs.readthedocs.io/
 [pytest]: https://docs.pytest.org/
+[pytest_approx]: https://docs.pytest.org/en/4.6.x/reference.html#pytest-approx
 [python]: https://www.python.org/
 [reim_michael]: https://elderlinux.org/
 [requests]: https://requests.readthedocs.io/
@@ -530,13 +531,15 @@ <h1>A Test Runner</h1>
 [selenium]: https://www.selenium.dev/
 [semver_spec]: https://semver.org/
 [sinel_joseph]: https://en.wikipedia.org/wiki/Joseph_Claude_Sinel
-[sphinx]: https://www.sphinx-doc.org/
+[snakemake]: https://snakemake.readthedocs.io/
 [sqlite]: https://sqlite.org/
 [stack_connor]: https://connorstack.com/
 [svg_screenshot]: https://chrome.google.com/webstore/detail/svg-screenshot/nfakpcpmhhilkdpphcjgnokknpbpdllg
 [t3_personas]: https://teachtogether.tech/en/index.html#s:process-personas
+[textualize_fraction]: https://www.textualize.io/blog/posts/7-things-about-terminals
 [udhr]: https://www.un.org/en/universal-declaration-human-rights/
 [ungc]: https://www.unglobalcompact.org/what-is-gc/mission/principles
+[unicode]: https://www.unicode.org/
 [unix_glob]: https://en.wikipedia.org/wiki/Glob_(programming)
 [unix_packaging]: https://eerielinux.wordpress.com/2017/08/15/the-history-of-nix-package-management/
 [webaim_wave]: https://wave.webaim.org/
diff --git a/docs/undo/slides/index.html b/docs/undo/slides/index.html
index 3026ec98d..995fde83c 100644
--- a/docs/undo/slides/index.html
+++ b/docs/undo/slides/index.html
@@ -4,7 +4,7 @@
   <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
   <meta name="viewport" content="width=device-width, initial-scale=1">
   <meta name="repo" content="https://github.com/gvwilson/sd4ds">
-  <meta name="build_date" content="2023-06-02">
+  <meta name="build_date" content="2023-06-03">
   <meta name="template" content="slides">
   <meta name="major" content="Chapter 24">
   
@@ -95,7 +95,6 @@ <h1>Undo and Redo</h1>
 [lorgat_tutorial]: https://wasimlorgat.com/posts/editor.html
 [lorgat_wasim]: https://wasimlorgat.com/
 [marthas_rules]: https://journals.sagepub.com/doi/10.1177/088610998600100206
-[mkdocs]: https://www.mkdocs.org/
 [nison_mael]: https://arcanis.github.io/
 [nystrom_bob]: http://journal.stuffwithstuff.com/
 [package_manager_tutorial]: https://classic.yarnpkg.com/blog/2017/07/11/lets-dev-a-package-manager/
@@ -110,6 +109,7 @@ <h1>Undo and Redo</h1>
 [py_ast]: https://docs.python.org/3/library/ast.html
 [py_chainmap]: https://docs.python.org/3/library/collections.html#collections.ChainMap
 [py_cprofile]: https://docs.python.org/3/library/profile.html
+[py_fractions]: https://docs.python.org/3/library/fractions.html
 [py_glob]: https://docs.python.org/3/library/glob.html
 [py_hashlib]: https://docs.python.org/3/library/hashlib.html
 [py_inspect]: https://docs.python.org/3/library/inspect.html
@@ -117,15 +117,16 @@ <h1>Undo and Redo</h1>
 [py_itertools]: https://docs.python.org/3/library/itertools.html
 [py_json]: https://docs.python.org/3/library/json.html
 [py_jsonschema]: https://python-jsonschema.readthedocs.io/
-[py_metaclass]: https://docs.python.org/3/reference/datamodel.html#metaclasses
 [py_mimetypes]: https://docs.python.org/3/library/mimetypes.html
 [py_pickle]: https://docs.python.org/3/library/pickle.html
 [py_property]: https://docs.python.org/3/library/functions.html#property
 [py_semver]: https://pypi.org/project/semantic-version/
+[py_struct]: https://docs.python.org/3/library/struct.html
 [py_textwrap]: https://docs.python.org/3/library/textwrap.html
 [py_urlparse]: https://docs.python.org/3/library/urllib.parse.html
 [pyfakefs]: https://pytest-pyfakefs.readthedocs.io/
 [pytest]: https://docs.pytest.org/
+[pytest_approx]: https://docs.pytest.org/en/4.6.x/reference.html#pytest-approx
 [python]: https://www.python.org/
 [reim_michael]: https://elderlinux.org/
 [requests]: https://requests.readthedocs.io/
@@ -133,13 +134,15 @@ <h1>Undo and Redo</h1>
 [selenium]: https://www.selenium.dev/
 [semver_spec]: https://semver.org/
 [sinel_joseph]: https://en.wikipedia.org/wiki/Joseph_Claude_Sinel
-[sphinx]: https://www.sphinx-doc.org/
+[snakemake]: https://snakemake.readthedocs.io/
 [sqlite]: https://sqlite.org/
 [stack_connor]: https://connorstack.com/
 [svg_screenshot]: https://chrome.google.com/webstore/detail/svg-screenshot/nfakpcpmhhilkdpphcjgnokknpbpdllg
 [t3_personas]: https://teachtogether.tech/en/index.html#s:process-personas
+[textualize_fraction]: https://www.textualize.io/blog/posts/7-things-about-terminals
 [udhr]: https://www.un.org/en/universal-declaration-human-rights/
 [ungc]: https://www.unglobalcompact.org/what-is-gc/mission/principles
+[unicode]: https://www.unicode.org/
 [unix_glob]: https://en.wikipedia.org/wiki/Glob_(programming)
 [unix_packaging]: https://eerielinux.wordpress.com/2017/08/15/the-history-of-nix-package-management/
 [webaim_wave]: https://wave.webaim.org/
diff --git a/docs/vm/slides/index.html b/docs/vm/slides/index.html
index eef55206f..1d77fc463 100644
--- a/docs/vm/slides/index.html
+++ b/docs/vm/slides/index.html
@@ -4,7 +4,7 @@
   <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
   <meta name="viewport" content="width=device-width, initial-scale=1">
   <meta name="repo" content="https://github.com/gvwilson/sd4ds">
-  <meta name="build_date" content="2023-06-02">
+  <meta name="build_date" content="2023-06-03">
   <meta name="template" content="slides">
   <meta name="major" content="Chapter 25">
   
@@ -513,7 +513,6 @@ <h1>A Virtual Machine</h1>
 [lorgat_tutorial]: https://wasimlorgat.com/posts/editor.html
 [lorgat_wasim]: https://wasimlorgat.com/
 [marthas_rules]: https://journals.sagepub.com/doi/10.1177/088610998600100206
-[mkdocs]: https://www.mkdocs.org/
 [nison_mael]: https://arcanis.github.io/
 [nystrom_bob]: http://journal.stuffwithstuff.com/
 [package_manager_tutorial]: https://classic.yarnpkg.com/blog/2017/07/11/lets-dev-a-package-manager/
@@ -528,6 +527,7 @@ <h1>A Virtual Machine</h1>
 [py_ast]: https://docs.python.org/3/library/ast.html
 [py_chainmap]: https://docs.python.org/3/library/collections.html#collections.ChainMap
 [py_cprofile]: https://docs.python.org/3/library/profile.html
+[py_fractions]: https://docs.python.org/3/library/fractions.html
 [py_glob]: https://docs.python.org/3/library/glob.html
 [py_hashlib]: https://docs.python.org/3/library/hashlib.html
 [py_inspect]: https://docs.python.org/3/library/inspect.html
@@ -535,15 +535,16 @@ <h1>A Virtual Machine</h1>
 [py_itertools]: https://docs.python.org/3/library/itertools.html
 [py_json]: https://docs.python.org/3/library/json.html
 [py_jsonschema]: https://python-jsonschema.readthedocs.io/
-[py_metaclass]: https://docs.python.org/3/reference/datamodel.html#metaclasses
 [py_mimetypes]: https://docs.python.org/3/library/mimetypes.html
 [py_pickle]: https://docs.python.org/3/library/pickle.html
 [py_property]: https://docs.python.org/3/library/functions.html#property
 [py_semver]: https://pypi.org/project/semantic-version/
+[py_struct]: https://docs.python.org/3/library/struct.html
 [py_textwrap]: https://docs.python.org/3/library/textwrap.html
 [py_urlparse]: https://docs.python.org/3/library/urllib.parse.html
 [pyfakefs]: https://pytest-pyfakefs.readthedocs.io/
 [pytest]: https://docs.pytest.org/
+[pytest_approx]: https://docs.pytest.org/en/4.6.x/reference.html#pytest-approx
 [python]: https://www.python.org/
 [reim_michael]: https://elderlinux.org/
 [requests]: https://requests.readthedocs.io/
@@ -551,13 +552,15 @@ <h1>A Virtual Machine</h1>
 [selenium]: https://www.selenium.dev/
 [semver_spec]: https://semver.org/
 [sinel_joseph]: https://en.wikipedia.org/wiki/Joseph_Claude_Sinel
-[sphinx]: https://www.sphinx-doc.org/
+[snakemake]: https://snakemake.readthedocs.io/
 [sqlite]: https://sqlite.org/
 [stack_connor]: https://connorstack.com/
 [svg_screenshot]: https://chrome.google.com/webstore/detail/svg-screenshot/nfakpcpmhhilkdpphcjgnokknpbpdllg
 [t3_personas]: https://teachtogether.tech/en/index.html#s:process-personas
+[textualize_fraction]: https://www.textualize.io/blog/posts/7-things-about-terminals
 [udhr]: https://www.un.org/en/universal-declaration-human-rights/
 [ungc]: https://www.unglobalcompact.org/what-is-gc/mission/principles
+[unicode]: https://www.unicode.org/
 [unix_glob]: https://en.wikipedia.org/wiki/Glob_(programming)
 [unix_packaging]: https://eerielinux.wordpress.com/2017/08/15/the-history-of-nix-package-management/
 [webaim_wave]: https://wave.webaim.org/
diff --git a/foo b/foo
new file mode 100644
index 000000000..6482dcab3
--- /dev/null
+++ b/foo
@@ -0,0 +1,187 @@
+ivy build && touch docs/index.html
+[06:23:23]   ·   Rendered:    64   ·   Written:    30   ·   Time:   4.23 sec
+src/intro: inclusions
+- extra
+  - gvwilson-gage-2019.png
+src/test: inclusions
+- extra
+  - attribute.out
+  - callable.out
+  - callable.py
+  - concept_map.pdf
+  - concept_map.svg
+  - signature.out
+  - signature.py
+  - type_len.out
+  - type_len.py
+src/template: inclusions
+- extra
+  - conditional.sh
+  - loop.sh
+  - loop.xml
+  - multiple_variables.sh
+  - single_constant.sh
+  - single_variable.sh
+  - static_text.sh
+src/oop: inclusions
+- extra
+  - people_multiple.out
+  - people_multiple.py
+  - people_original.out
+  - people_original.py
+  - shapes_class.out
+  - shapes_dict.out
+  - shapes_original.out
+src/dup: inclusions
+- extra
+  - dracula.txt
+  - grouped.sh
+  - naive_dracula.py
+  - sha256_dracula.pdf
+  - sha256_dracula.py
+  - sha256_dracula.svg
+  - tests/a1.txt
+  - tests/a2.txt
+  - tests/a3.txt
+  - tests/b1.txt
+  - tests/b2.txt
+  - tests/c1.txt
+src/undo: inclusions
+- extra
+  - wasim.py
+src/vm: inclusions
+- extra
+  - count_up_assemble.sh
+  - count_up_run.sh
+  - fill_array.as
+  - fill_array.mx
+  - fill_array.out
+  - fill_array_assemble.sh
+  - fill_array_run.sh
+  - halt.as
+  - halt.mx
+  - halt.out
+  - halt_assemble.sh
+  - halt_run.sh
+  - print_r1.out
+  - print_r1_assemble.sh
+  - print_r1_run.sh
+src/debugger: inclusions
+- extra
+  - assembler.py
+  - fill_array.as
+  - fill_array.mx
+  - halt.as
+  - halt.mx
+  - print_num.as
+  - print_num.mx
+src/glob: inclusions
+- extra
+  - fowler-refactoring.webp
+  - gamma-design-patterns.webp
+  - kerievsky-refactoring-to-patterns.webp
+  - simpler_match.py
+  - test_glob_null.py
+  - test_simpler_match.py
+src/binary: inclusions
+- extra
+  - bird.txt
+  - dynamic_format.out
+  - dynamic_format.py
+  - endian.pdf
+  - endian.svg
+  - hex_notation.out
+  - hex_notation.py
+  - pack_unicode.out
+  - pack_unicode.py
+src/build: inclusions
+- extra
+  - circular.json
+  - compiling.pdf
+  - compiling.svg
+  - diamond.json
+  - double_linear_dep.sh
+  - double_no_dep.json
+  - empty.json
+  - single_no_dep.json
+src/perf: inclusions
+- extra
+  - analysis.py
+  - hennessy-patterson.jpg
+  - make.out
+  - make.py
+  - timing.csv
+  - timing.sh
+src/check: inclusions
+- extra
+  - catalog.out
+  - catalog.sh
+  - check.sh
+  - contains.sh
+src/persist: inclusions
+- extra
+  - shared.py
+src/editor: inclusions
+- extra
+  - controller_cursor.py
+  - controller_editor.py
+  - controller_original.py
+  - controller_up_down.py
+  - controller_viewport.py
+  - curses_wrapper.py
+  - main_cursor.py
+  - main_editor.py
+  - main_show_lines.py
+  - main_slice.py
+  - main_up_down.py
+  - main_up_down_fixed.py
+  - main_viewport.py
+  - model_editor.py
+  - model_original.py
+  - recorder.py
+  - test_original.py
+  - test_viewport.py
+  - utils.py
+  - view_cursor.py
+  - view_original.py
+  - view_show_lines.py
+  - view_slice.py
+  - view_up_down.py
+  - view_up_down_fixed.py
+  - viewport_editor.py
+  - viewport_viewport.py
+src/func: inclusions
+- extra
+  - dynamic.out
+  - dynamic.sh
+  - dynamic.tll
+  - func.sh
+  - wrap_infinite.out
+  - wrap_infinite.sh
+links
+- extra
+  - mkdocs
+  - py_metaclass
+  - sphinx
+b seen but not expected
+body.class seen but not expected
+class seen but not expected
+dictcomp seen but not expected
+div.class == 'bonus' seen but not expected
+div.class == 'lang-html' seen but not expected
+div.class == 'lang-txt' seen but not expected
+div.class == 'small' seen but not expected
+figure.class seen but not expected
+function seen but not expected
+genexpr seen but not expected
+h2.class seen but not expected
+module seen but not expected
+p.align seen but not expected
+p.z-if seen but not expected
+span.z-num seen but not expected
+span.z-var seen but not expected
+sub seen but not expected
+tag seen but not expected
+td.style seen but not expected
+th.style seen but not expected
+ul.z-loop seen but not expected
diff --git a/info/links.yml b/info/links.yml
index 8d1eb87f1..81bb01e46 100644
--- a/info/links.yml
+++ b/info/links.yml
@@ -186,9 +186,6 @@
 - key: marthas_rules
   url: https://journals.sagepub.com/doi/10.1177/088610998600100206
   en: Martha's Rules
-- key: mkdocs
-  url: https://www.mkdocs.org/
-  en: MkDocs
 
 # N
 
@@ -239,6 +236,9 @@
 - key: py_cprofile
   url: https://docs.python.org/3/library/profile.html
   en: Python profile module
+- key: py_fractions
+  url: https://docs.python.org/3/library/fractions.html
+  en: Python fractions module
 - key: py_glob
   url: https://docs.python.org/3/library/glob.html
   en: Python glob module
@@ -260,9 +260,6 @@
 - key: py_jsonschema
   url: https://python-jsonschema.readthedocs.io/
   en: Python JSON schema module
-- key: py_metaclass
-  url: https://docs.python.org/3/reference/datamodel.html#metaclasses
-  en: Python metaclasses
 - key: py_mimetypes
   url: https://docs.python.org/3/library/mimetypes.html
   en: Python mimetypes module
@@ -275,6 +272,9 @@
 - key: py_semver
   url: https://pypi.org/project/semantic-version/
   en: Python semantic version module
+- key: py_struct
+  url: https://docs.python.org/3/library/struct.html
+  en: Python struct module
 - key: py_textwrap
   url: https://docs.python.org/3/library/textwrap.html
   en: Python textwrap module
@@ -287,6 +287,9 @@
 - key: pytest
   url: https://docs.pytest.org/
   en: pytest testing framework
+- key: pytest_approx
+  url: https://docs.pytest.org/en/4.6.x/reference.html#pytest-approx
+  en: pytest approximate equality
 - key: python
   url: https://www.python.org/
   en: Python
@@ -316,9 +319,9 @@
 - key: sinel_joseph
   url: https://en.wikipedia.org/wiki/Joseph_Claude_Sinel
   en: Joseph Sinel
-- key: sphinx
-  url: https://www.sphinx-doc.org/
-  en: Sphinx
+- key: snakemake
+  url: https://snakemake.readthedocs.io/
+  en: Snakemake
 - key: sqlite
   url: https://sqlite.org/
   en: SQLite
@@ -334,6 +337,9 @@
 - key: t3_personas
   url: https://teachtogether.tech/en/index.html#s:process-personas
   en: Learner personas
+- key: textualize_fraction
+  url: https://www.textualize.io/blog/posts/7-things-about-terminals
+  en: "A clever use of the `Fraction` package"
 
 # U
 
@@ -343,6 +349,9 @@
 - key: ungc
   url: https://www.unglobalcompact.org/what-is-gc/mission/principles
   en: United Nations Global Compact
+- key: unicode
+  url: https://www.unicode.org/
+  en: Unicode Consortium
 - key: unix_glob
   url: "https://en.wikipedia.org/wiki/Glob_(programming)"
   en: globbing
diff --git a/src/archive/.mccole b/src/archive/.mccole
index b6188cfde..59851595d 100644
--- a/src/archive/.mccole
+++ b/src/archive/.mccole
@@ -1,2 +1,5 @@
 exclude:
 - sample_dir
+unreferenced:
+- sample_dir/*
+- sample_dir.sh
diff --git a/src/db/.mccole b/src/db/.mccole
new file mode 100644
index 000000000..d10820f23
--- /dev/null
+++ b/src/db/.mccole
@@ -0,0 +1,3 @@
+unreferenced:
+- test_db.py
+- test_records.py
diff --git a/src/interp/.mccole b/src/interp/.mccole
new file mode 100644
index 000000000..109021b06
--- /dev/null
+++ b/src/interp/.mccole
@@ -0,0 +1,3 @@
+unreferenced:
+- doubling.sh
+- vars.sh
diff --git a/src/intro/slides.html b/src/intro/slides.html
index c20789fa7..945d5d221 100644
--- a/src/intro/slides.html
+++ b/src/intro/slides.html
@@ -129,7 +129,7 @@
 
 <div class="center">
   <em>
-    This one's for Mike and both Jons:
+    This one's for Mike and Jon:
     <br>
     I'm glad you always found time to chat.
   </em>
diff --git a/src/layout/.mccole b/src/layout/.mccole
new file mode 100644
index 000000000..b047d4001
--- /dev/null
+++ b/src/layout/.mccole
@@ -0,0 +1,4 @@
+unreferenced:
+- test_easy_mode.sh
+- test_placed.sh
+- test_wrapped.sh
diff --git a/src/lint/.mccole b/src/lint/.mccole
new file mode 100644
index 000000000..dad99c24a
--- /dev/null
+++ b/src/lint/.mccole
@@ -0,0 +1,6 @@
+unreferenced:
+- double.py
+- find_duplicate_keys.sh
+- find_unused_variables.sh
+- inheritance_example.out
+- inheritance_example.sh
diff --git a/src/pack/.mccole b/src/pack/.mccole
new file mode 100644
index 000000000..f5b4f1a30
--- /dev/null
+++ b/src/pack/.mccole
@@ -0,0 +1,3 @@
+unreferenced:
+- exhaustive.sh
+- manual.sh
diff --git a/src/pack/index.md b/src/pack/index.md
index 2d65e2d08..088330d51 100644
--- a/src/pack/index.md
+++ b/src/pack/index.md
@@ -218,6 +218,7 @@ the recursive calls must have included exactly one version of each package,
 so the combination is appended to the accumulator.
 
 [% inc file="manual.py" keep="make" %]
+[% inc file="manual.out" %]
 
 [% figure
    slug="pack-recursive"
diff --git a/src/parse/.mccole b/src/parse/.mccole
new file mode 100644
index 000000000..abba05377
--- /dev/null
+++ b/src/parse/.mccole
@@ -0,0 +1,2 @@
+unreferenced:
+- test_better_parser.py
diff --git a/unused/links.yml b/unused/links.yml
index 15488e854..bade05b03 100644
--- a/unused/links.yml
+++ b/unused/links.yml
@@ -16,6 +16,9 @@
 - key: log_structured_storage
   url: http://blog.notdot.net/2009/12/Damn-Cool-Algorithms-Log-structured-storage
   en: "Damn Cool Algorithms: Log structured storage"
+- key: mkdocs
+  url: https://www.mkdocs.org/
+  en: MkDocs
 - key: nash_joe
   url: https://hachyderm.io/@joenash
   en: Joe Nash
@@ -25,33 +28,18 @@
 - key: pereira_juanan
   url: https://ikasten.io/
   en: Juanan Pereira
-- key: py_fractions
-  url: https://docs.python.org/3/library/fractions.html
-  en: Python fractions module
-- key: py_struct
-  url: https://docs.python.org/3/library/struct.html
-  en: Python struct module
 - key: py_yaml
   url: https://pypi.org/project/PyYAML/
   en: Python YAML module
 - key: py_zipfile
   url: https://docs.python.org/3/library/zipfile.html
   en: Python ZIP archive module
-- key: pytest_approx
-  url: https://docs.pytest.org/en/4.6.x/reference.html#pytest-approx
-  en: pytest approximate equality
 - key: pytest_stdout
   url: https://docs.pytest.org/en/6.2.x/capture.html
   en: Capturing standard output with pytest
 - key: smith_dave
   url: https://davewsmith.com/
   en: Dave Smith
-- key: snakemake
-  url: https://snakemake.readthedocs.io/
-  en: Snakemake
-- key: textualize_fraction
-  url: https://www.textualize.io/blog/posts/7-things-about-terminals
-  en: "A clever use of the `Fraction` package"
-- key: unicode
-  url: https://www.unicode.org/
-  en: Unicode Consortium
+- key: sphinx
+  url: https://www.sphinx-doc.org/
+  en: Sphinx