diff --git a/signwriting/fingerspelling/data/en-us-ase-asl.txt b/signwriting/fingerspelling/data/en-us-ase-asl.txt
index d62a977..3f8d519 100644
--- a/signwriting/fingerspelling/data/en-us-ase-asl.txt
+++ b/signwriting/fingerspelling/data/en-us-ase-asl.txt
@@ -36,4 +36,6 @@ Z,M528x507S10020492x477S2450a497x473
 8,M511x514S1bb20492x486
 9,M511x515S1ce20493x485
 0,M508x508S17620493x492
-@,M510x524S1f720488x487S2f104492x507S21600496x475,M512x528S1f720488x481S2e308488x501S2f900495x473,M512x523S1f720488x478S2e300487x496
\ No newline at end of file
+@,M510x524S1f720488x487S2f104492x507S21600496x475,M512x528S1f720488x481S2e308488x501S2f900495x473,M512x523S1f720488x478S2e300487x496
+.,M512x522S2f900498x479S26500497x488S1eb20488x503
+/,M522x522S15a41478x478S22b05498x498
\ No newline at end of file
diff --git a/signwriting/fingerspelling/fingerspelling.py b/signwriting/fingerspelling/fingerspelling.py
index e27e78e..4279b51 100644
--- a/signwriting/fingerspelling/fingerspelling.py
+++ b/signwriting/fingerspelling/fingerspelling.py
@@ -57,5 +57,6 @@ def spell(word: str, language=None, chars=None, vertical=True) -> Union[str, Non
 
 
 if __name__ == "__main__":
-    for _word in ["12345", "hello", "Amit"]:
-        print(_word, spell(_word, language='en-us-ase-asl', vertical=False))
+    words = ["custom", "prited", "circuit", "board"]
+    spellings = [spell(word, language='en-us-ase-asl', vertical=True) for word in words]
+    print(" ".join(spellings))
diff --git a/signwriting/fingerspelling/test_fingerspelling.py b/signwriting/fingerspelling/test_fingerspelling.py
new file mode 100644
index 0000000..626cd39
--- /dev/null
+++ b/signwriting/fingerspelling/test_fingerspelling.py
@@ -0,0 +1,19 @@
+import unittest
+
+from signwriting.fingerspelling.fingerspelling import spell
+
+
+class FingerspellingCase(unittest.TestCase):
+
+    def test_successful_spelling(self):
+        sign = spell("abc", language='en-us-ase-asl', vertical=True)
+        self.assertEqual(sign, "M510x533S1f720487x466S14720493x486S16d20491x513")
+
+    def test_unsuccessful_spelling_throws(self):
+        long_word = "abcdefghijklmnopqrstuvwxyz"
+        with self.assertRaises(ValueError):
+            spell(long_word, language='en-us-ase-asl', vertical=True)
+
+
+if __name__ == '__main__':
+    unittest.main()
diff --git a/signwriting/formats/sign_to_fsw.py b/signwriting/formats/sign_to_fsw.py
index f797368..147a2bc 100644
--- a/signwriting/formats/sign_to_fsw.py
+++ b/signwriting/formats/sign_to_fsw.py
@@ -1,7 +1,12 @@
+from itertools import chain
+
 from signwriting.types import Sign
 
 
 def sign_to_fsw(sign: Sign) -> str:
     symbols = [sign["box"]] + sign["symbols"]
+    all_positions = list(chain.from_iterable([s["position"] for s in symbols]))
+    if min(all_positions) < 250 or max(all_positions) > 750:
+        raise ValueError("Positions must be between 250 and 750")
     symbols_str = [s["symbol"] + str(s["position"][0]) + 'x' + str(s["position"][1]) for s in symbols]
     return "".join(symbols_str)