diff --git a/gauguin-app/src/test/kotlin/org/piepmeyer/gauguin/ui/newgame/GridPreviewCalculationServiceMock.kt b/gauguin-app/src/test/kotlin/org/piepmeyer/gauguin/ui/newgame/GridPreviewCalculationServiceMock.kt
new file mode 100644
index 00000000..a0322e41
--- /dev/null
+++ b/gauguin-app/src/test/kotlin/org/piepmeyer/gauguin/ui/newgame/GridPreviewCalculationServiceMock.kt
@@ -0,0 +1,19 @@
+package org.piepmeyer.gauguin.ui.newgame
+
+import kotlinx.coroutines.CoroutineScope
+import org.piepmeyer.gauguin.calculation.GridPreviewCalculationService
+import org.piepmeyer.gauguin.grid.Grid
+import org.piepmeyer.gauguin.options.GameVariant
+
+class GridPreviewCalculationServiceMock(
+    private val grid: Grid,
+) : GridPreviewCalculationService() {
+    override fun calculateGrid(
+        variant: GameVariant,
+        scope: CoroutineScope,
+    ) {
+        listeners.forEach {
+            it.previewGridCalculated(grid)
+        }
+    }
+}
diff --git a/gauguin-app/src/test/kotlin/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest.kt b/gauguin-app/src/test/kotlin/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest.kt
index 9d4af3e0..a2c7fdad 100644
--- a/gauguin-app/src/test/kotlin/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest.kt
+++ b/gauguin-app/src/test/kotlin/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest.kt
@@ -3,7 +3,9 @@ package org.piepmeyer.gauguin.ui.newgame
 import com.github.takahirom.roborazzi.captureRoboImage
 import com.google.android.material.tabs.TabLayout
 import io.mockk.every
+import io.mockk.just
 import io.mockk.mockk
+import io.mockk.runs
 import org.junit.After
 import org.junit.Before
 import org.junit.Rule
@@ -19,6 +21,8 @@ import org.piepmeyer.gauguin.R
 import org.piepmeyer.gauguin.ScreenshotTest
 import org.piepmeyer.gauguin.ScreenshotTestUtils
 import org.piepmeyer.gauguin.Theme
+import org.piepmeyer.gauguin.calculation.GridCalculationService
+import org.piepmeyer.gauguin.calculation.GridPreviewCalculationService
 import org.piepmeyer.gauguin.creation.GridCreator
 import org.piepmeyer.gauguin.creation.RandomPossibleDigitsShuffler
 import org.piepmeyer.gauguin.creation.SeedRandomizerMock
@@ -32,7 +36,6 @@ import org.piepmeyer.gauguin.options.GridCageOperation
 import org.piepmeyer.gauguin.options.NumeralSystem
 import org.piepmeyer.gauguin.options.SingleCageUsage
 import org.piepmeyer.gauguin.preferences.ApplicationPreferences
-import org.piepmeyer.gauguin.ui.grid.GridUI
 import org.robolectric.ParameterizedRobolectricTestRunner
 import org.robolectric.annotation.Config
 import org.robolectric.annotation.GraphicsMode
@@ -101,11 +104,27 @@ class NewGameActivityScreenshotTest(
                         every { numeralSystem } returns NumeralSystem.Decimal
                         every { operations } returns GridCageOperation.OPERATIONS_ALL
                         every { singleCageUsage } returns SingleCageUsage.FIXED_NUMBER
-                        every { gridWidth } returns 9
-                        every { gridHeigth } returns 9
-                        every { gameVariant } returns GameOptionsVariant.createClassic()
+                        every { gridWidth } returns 6
+                        every { gridHeigth } returns 6
+                        every { squareOnlyGrid } returns true
+                        every { gameOptionsVariant } returns GameOptionsVariant.createClassic()
                     }
                 } withOptions { binds(listOf(ApplicationPreferences::class)) }
+                /*single {
+                    GridPreviewCalculationServiceMock(createDefaultGrid())
+                } withOptions { binds(listOf(GridPreviewCalculationService::class)) }*/
+                single {
+                    mockk<GridPreviewCalculationService>(relaxed = true) {
+                        every { takeCalculatedGrid(any()) } just runs
+                        every { calculateGrid(any(), any()) } just runs
+                    }
+                } withOptions { binds(listOf(GridPreviewCalculationService::class)) }
+                single {
+                    mockk<GridCalculationService>(relaxed = true) {
+                        every { hasCalculatedNextGrid(any()) } returns true
+                        every { consumeNextGrid() } returns createDefaultGrid()
+                    }
+                } withOptions { binds(listOf(GridCalculationService::class)) }
             }
     }
 
@@ -118,8 +137,6 @@ class NewGameActivityScreenshotTest(
     @Test
     fun screenshotTest() {
         robolectricScreenshotRule.activityScenario.onActivity {
-            it.findViewById<GridUI>(R.id.newGridPreview).grid = createDefaultGrid()
-
             val tabs = it.findViewById<TabLayout>(R.id.new_game_options_tablayout)
 
             when (testItem.uiState) {
@@ -127,6 +144,8 @@ class NewGameActivityScreenshotTest(
                 UiStateEnum.TabNumbers -> tabs.selectTab(tabs.getTabAt(1))
                 UiStateEnum.TabAdvanced -> tabs.selectTab(tabs.getTabAt(2))
             }
+
+            it.recreate()
         }
 
         robolectricScreenshotRule
diff --git a/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_LARGE_DESKTOP_DAY_FONT_NORMAL_LANDSCAPE_TabAdvanced.png b/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_LARGE_DESKTOP_DAY_FONT_NORMAL_LANDSCAPE_TabAdvanced.png
index fbf9a5c7..2831f3df 100644
Binary files a/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_LARGE_DESKTOP_DAY_FONT_NORMAL_LANDSCAPE_TabAdvanced.png and b/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_LARGE_DESKTOP_DAY_FONT_NORMAL_LANDSCAPE_TabAdvanced.png differ
diff --git a/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_LARGE_DESKTOP_DAY_FONT_NORMAL_LANDSCAPE_TabBasic.png b/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_LARGE_DESKTOP_DAY_FONT_NORMAL_LANDSCAPE_TabBasic.png
index ba3d0a41..2831f3df 100644
Binary files a/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_LARGE_DESKTOP_DAY_FONT_NORMAL_LANDSCAPE_TabBasic.png and b/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_LARGE_DESKTOP_DAY_FONT_NORMAL_LANDSCAPE_TabBasic.png differ
diff --git a/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_LARGE_DESKTOP_DAY_FONT_NORMAL_LANDSCAPE_TabNumbers.png b/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_LARGE_DESKTOP_DAY_FONT_NORMAL_LANDSCAPE_TabNumbers.png
index 5d6ed253..2831f3df 100644
Binary files a/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_LARGE_DESKTOP_DAY_FONT_NORMAL_LANDSCAPE_TabNumbers.png and b/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_LARGE_DESKTOP_DAY_FONT_NORMAL_LANDSCAPE_TabNumbers.png differ
diff --git a/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_LARGE_DESKTOP_DAY_FONT_NORMAL_PORTRAIT_TabAdvanced.png b/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_LARGE_DESKTOP_DAY_FONT_NORMAL_PORTRAIT_TabAdvanced.png
index 9913ccda..4636f61a 100644
Binary files a/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_LARGE_DESKTOP_DAY_FONT_NORMAL_PORTRAIT_TabAdvanced.png and b/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_LARGE_DESKTOP_DAY_FONT_NORMAL_PORTRAIT_TabAdvanced.png differ
diff --git a/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_LARGE_DESKTOP_DAY_FONT_NORMAL_PORTRAIT_TabBasic.png b/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_LARGE_DESKTOP_DAY_FONT_NORMAL_PORTRAIT_TabBasic.png
index e59cf3d5..4636f61a 100644
Binary files a/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_LARGE_DESKTOP_DAY_FONT_NORMAL_PORTRAIT_TabBasic.png and b/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_LARGE_DESKTOP_DAY_FONT_NORMAL_PORTRAIT_TabBasic.png differ
diff --git a/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_LARGE_DESKTOP_DAY_FONT_NORMAL_PORTRAIT_TabNumbers.png b/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_LARGE_DESKTOP_DAY_FONT_NORMAL_PORTRAIT_TabNumbers.png
index 8eefb986..4636f61a 100644
Binary files a/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_LARGE_DESKTOP_DAY_FONT_NORMAL_PORTRAIT_TabNumbers.png and b/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_LARGE_DESKTOP_DAY_FONT_NORMAL_PORTRAIT_TabNumbers.png differ
diff --git a/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_MEDIUM_TABLET_DAY_FONT_NORMAL_LANDSCAPE_TabAdvanced.png b/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_MEDIUM_TABLET_DAY_FONT_NORMAL_LANDSCAPE_TabAdvanced.png
index c3e4a6ad..50507149 100644
Binary files a/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_MEDIUM_TABLET_DAY_FONT_NORMAL_LANDSCAPE_TabAdvanced.png and b/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_MEDIUM_TABLET_DAY_FONT_NORMAL_LANDSCAPE_TabAdvanced.png differ
diff --git a/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_MEDIUM_TABLET_DAY_FONT_NORMAL_LANDSCAPE_TabBasic.png b/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_MEDIUM_TABLET_DAY_FONT_NORMAL_LANDSCAPE_TabBasic.png
index e3161d31..50507149 100644
Binary files a/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_MEDIUM_TABLET_DAY_FONT_NORMAL_LANDSCAPE_TabBasic.png and b/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_MEDIUM_TABLET_DAY_FONT_NORMAL_LANDSCAPE_TabBasic.png differ
diff --git a/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_MEDIUM_TABLET_DAY_FONT_NORMAL_LANDSCAPE_TabNumbers.png b/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_MEDIUM_TABLET_DAY_FONT_NORMAL_LANDSCAPE_TabNumbers.png
index 441f270d..50507149 100644
Binary files a/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_MEDIUM_TABLET_DAY_FONT_NORMAL_LANDSCAPE_TabNumbers.png and b/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_MEDIUM_TABLET_DAY_FONT_NORMAL_LANDSCAPE_TabNumbers.png differ
diff --git a/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_MEDIUM_TABLET_DAY_FONT_NORMAL_PORTRAIT_TabAdvanced.png b/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_MEDIUM_TABLET_DAY_FONT_NORMAL_PORTRAIT_TabAdvanced.png
index 621b726a..dcb3187c 100644
Binary files a/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_MEDIUM_TABLET_DAY_FONT_NORMAL_PORTRAIT_TabAdvanced.png and b/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_MEDIUM_TABLET_DAY_FONT_NORMAL_PORTRAIT_TabAdvanced.png differ
diff --git a/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_MEDIUM_TABLET_DAY_FONT_NORMAL_PORTRAIT_TabBasic.png b/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_MEDIUM_TABLET_DAY_FONT_NORMAL_PORTRAIT_TabBasic.png
index 9f01c8d4..dcb3187c 100644
Binary files a/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_MEDIUM_TABLET_DAY_FONT_NORMAL_PORTRAIT_TabBasic.png and b/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_MEDIUM_TABLET_DAY_FONT_NORMAL_PORTRAIT_TabBasic.png differ
diff --git a/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_MEDIUM_TABLET_DAY_FONT_NORMAL_PORTRAIT_TabNumbers.png b/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_MEDIUM_TABLET_DAY_FONT_NORMAL_PORTRAIT_TabNumbers.png
index 6a0a8973..dcb3187c 100644
Binary files a/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_MEDIUM_TABLET_DAY_FONT_NORMAL_PORTRAIT_TabNumbers.png and b/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_MEDIUM_TABLET_DAY_FONT_NORMAL_PORTRAIT_TabNumbers.png differ
diff --git a/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_NEXUS_ONE_DAY_FONT_NORMAL_LANDSCAPE_TabAdvanced.png b/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_NEXUS_ONE_DAY_FONT_NORMAL_LANDSCAPE_TabAdvanced.png
index f39611dd..eff0d09c 100644
Binary files a/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_NEXUS_ONE_DAY_FONT_NORMAL_LANDSCAPE_TabAdvanced.png and b/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_NEXUS_ONE_DAY_FONT_NORMAL_LANDSCAPE_TabAdvanced.png differ
diff --git a/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_NEXUS_ONE_DAY_FONT_NORMAL_LANDSCAPE_TabBasic.png b/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_NEXUS_ONE_DAY_FONT_NORMAL_LANDSCAPE_TabBasic.png
index 32d6f9c1..eff0d09c 100644
Binary files a/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_NEXUS_ONE_DAY_FONT_NORMAL_LANDSCAPE_TabBasic.png and b/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_NEXUS_ONE_DAY_FONT_NORMAL_LANDSCAPE_TabBasic.png differ
diff --git a/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_NEXUS_ONE_DAY_FONT_NORMAL_LANDSCAPE_TabNumbers.png b/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_NEXUS_ONE_DAY_FONT_NORMAL_LANDSCAPE_TabNumbers.png
index 9c7adf86..eff0d09c 100644
Binary files a/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_NEXUS_ONE_DAY_FONT_NORMAL_LANDSCAPE_TabNumbers.png and b/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_NEXUS_ONE_DAY_FONT_NORMAL_LANDSCAPE_TabNumbers.png differ
diff --git a/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_NEXUS_ONE_DAY_FONT_NORMAL_PORTRAIT_TabAdvanced.png b/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_NEXUS_ONE_DAY_FONT_NORMAL_PORTRAIT_TabAdvanced.png
index d466b0ae..cde4928e 100644
Binary files a/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_NEXUS_ONE_DAY_FONT_NORMAL_PORTRAIT_TabAdvanced.png and b/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_NEXUS_ONE_DAY_FONT_NORMAL_PORTRAIT_TabAdvanced.png differ
diff --git a/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_NEXUS_ONE_DAY_FONT_NORMAL_PORTRAIT_TabBasic.png b/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_NEXUS_ONE_DAY_FONT_NORMAL_PORTRAIT_TabBasic.png
index 165c0f62..b843ba38 100644
Binary files a/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_NEXUS_ONE_DAY_FONT_NORMAL_PORTRAIT_TabBasic.png and b/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_NEXUS_ONE_DAY_FONT_NORMAL_PORTRAIT_TabBasic.png differ
diff --git a/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_NEXUS_ONE_DAY_FONT_NORMAL_PORTRAIT_TabNumbers.png b/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_NEXUS_ONE_DAY_FONT_NORMAL_PORTRAIT_TabNumbers.png
index 76c79388..cde4928e 100644
Binary files a/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_NEXUS_ONE_DAY_FONT_NORMAL_PORTRAIT_TabNumbers.png and b/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_NEXUS_ONE_DAY_FONT_NORMAL_PORTRAIT_TabNumbers.png differ
diff --git a/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_PIXEL_4A_DAY_FONT_NORMAL_LANDSCAPE_TabAdvanced.png b/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_PIXEL_4A_DAY_FONT_NORMAL_LANDSCAPE_TabAdvanced.png
index 324e9ee3..d05add6b 100644
Binary files a/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_PIXEL_4A_DAY_FONT_NORMAL_LANDSCAPE_TabAdvanced.png and b/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_PIXEL_4A_DAY_FONT_NORMAL_LANDSCAPE_TabAdvanced.png differ
diff --git a/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_PIXEL_4A_DAY_FONT_NORMAL_LANDSCAPE_TabBasic.png b/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_PIXEL_4A_DAY_FONT_NORMAL_LANDSCAPE_TabBasic.png
index 8e18c660..d05add6b 100644
Binary files a/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_PIXEL_4A_DAY_FONT_NORMAL_LANDSCAPE_TabBasic.png and b/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_PIXEL_4A_DAY_FONT_NORMAL_LANDSCAPE_TabBasic.png differ
diff --git a/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_PIXEL_4A_DAY_FONT_NORMAL_LANDSCAPE_TabNumbers.png b/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_PIXEL_4A_DAY_FONT_NORMAL_LANDSCAPE_TabNumbers.png
index d02301ce..d05add6b 100644
Binary files a/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_PIXEL_4A_DAY_FONT_NORMAL_LANDSCAPE_TabNumbers.png and b/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_PIXEL_4A_DAY_FONT_NORMAL_LANDSCAPE_TabNumbers.png differ
diff --git a/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_PIXEL_4A_DAY_FONT_NORMAL_PORTRAIT_TabAdvanced.png b/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_PIXEL_4A_DAY_FONT_NORMAL_PORTRAIT_TabAdvanced.png
index 15103698..ce46568e 100644
Binary files a/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_PIXEL_4A_DAY_FONT_NORMAL_PORTRAIT_TabAdvanced.png and b/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_PIXEL_4A_DAY_FONT_NORMAL_PORTRAIT_TabAdvanced.png differ
diff --git a/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_PIXEL_4A_DAY_FONT_NORMAL_PORTRAIT_TabBasic.png b/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_PIXEL_4A_DAY_FONT_NORMAL_PORTRAIT_TabBasic.png
index d9d38f27..ce46568e 100644
Binary files a/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_PIXEL_4A_DAY_FONT_NORMAL_PORTRAIT_TabBasic.png and b/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_PIXEL_4A_DAY_FONT_NORMAL_PORTRAIT_TabBasic.png differ
diff --git a/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_PIXEL_4A_DAY_FONT_NORMAL_PORTRAIT_TabNumbers.png b/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_PIXEL_4A_DAY_FONT_NORMAL_PORTRAIT_TabNumbers.png
index f7943218..ce46568e 100644
Binary files a/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_PIXEL_4A_DAY_FONT_NORMAL_PORTRAIT_TabNumbers.png and b/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_PIXEL_4A_DAY_FONT_NORMAL_PORTRAIT_TabNumbers.png differ
diff --git a/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_SMALL_PHONE_DAY_FONT_NORMAL_LANDSCAPE_TabAdvanced.png b/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_SMALL_PHONE_DAY_FONT_NORMAL_LANDSCAPE_TabAdvanced.png
index ecefa46f..57dd6765 100644
Binary files a/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_SMALL_PHONE_DAY_FONT_NORMAL_LANDSCAPE_TabAdvanced.png and b/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_SMALL_PHONE_DAY_FONT_NORMAL_LANDSCAPE_TabAdvanced.png differ
diff --git a/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_SMALL_PHONE_DAY_FONT_NORMAL_LANDSCAPE_TabBasic.png b/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_SMALL_PHONE_DAY_FONT_NORMAL_LANDSCAPE_TabBasic.png
index cd71c118..57dd6765 100644
Binary files a/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_SMALL_PHONE_DAY_FONT_NORMAL_LANDSCAPE_TabBasic.png and b/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_SMALL_PHONE_DAY_FONT_NORMAL_LANDSCAPE_TabBasic.png differ
diff --git a/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_SMALL_PHONE_DAY_FONT_NORMAL_LANDSCAPE_TabNumbers.png b/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_SMALL_PHONE_DAY_FONT_NORMAL_LANDSCAPE_TabNumbers.png
index ab741857..57dd6765 100644
Binary files a/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_SMALL_PHONE_DAY_FONT_NORMAL_LANDSCAPE_TabNumbers.png and b/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_SMALL_PHONE_DAY_FONT_NORMAL_LANDSCAPE_TabNumbers.png differ
diff --git a/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_SMALL_PHONE_DAY_FONT_NORMAL_PORTRAIT_TabAdvanced.png b/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_SMALL_PHONE_DAY_FONT_NORMAL_PORTRAIT_TabAdvanced.png
index 19cca2c0..a5d19c0f 100644
Binary files a/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_SMALL_PHONE_DAY_FONT_NORMAL_PORTRAIT_TabAdvanced.png and b/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_SMALL_PHONE_DAY_FONT_NORMAL_PORTRAIT_TabAdvanced.png differ
diff --git a/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_SMALL_PHONE_DAY_FONT_NORMAL_PORTRAIT_TabBasic.png b/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_SMALL_PHONE_DAY_FONT_NORMAL_PORTRAIT_TabBasic.png
index 562a2c69..a5d19c0f 100644
Binary files a/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_SMALL_PHONE_DAY_FONT_NORMAL_PORTRAIT_TabBasic.png and b/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_SMALL_PHONE_DAY_FONT_NORMAL_PORTRAIT_TabBasic.png differ
diff --git a/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_SMALL_PHONE_DAY_FONT_NORMAL_PORTRAIT_TabNumbers.png b/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_SMALL_PHONE_DAY_FONT_NORMAL_PORTRAIT_TabNumbers.png
index 9f6140f3..a5d19c0f 100644
Binary files a/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_SMALL_PHONE_DAY_FONT_NORMAL_PORTRAIT_TabNumbers.png and b/gauguin-app/src/test/resources/org/piepmeyer/gauguin/ui/newgame/NewGameActivityScreenshotTest_SMALL_PHONE_DAY_FONT_NORMAL_PORTRAIT_TabNumbers.png differ
diff --git a/gauguin-core/src/main/kotlin/org/piepmeyer/gauguin/calculation/GridPreviewCalculationService.kt b/gauguin-core/src/main/kotlin/org/piepmeyer/gauguin/calculation/GridPreviewCalculationService.kt
index f70abd9e..43e5e474 100644
--- a/gauguin-core/src/main/kotlin/org/piepmeyer/gauguin/calculation/GridPreviewCalculationService.kt
+++ b/gauguin-core/src/main/kotlin/org/piepmeyer/gauguin/calculation/GridPreviewCalculationService.kt
@@ -19,11 +19,11 @@ import java.util.WeakHashMap
 
 private val logger = KotlinLogging.logger {}
 
-class GridPreviewCalculationService(
+open class GridPreviewCalculationService(
     private val dispatcher: CoroutineDispatcher = Dispatchers.Default,
 ) {
     private val grids: MutableMap<GameVariant, Grid> = WeakHashMap()
-    private var listeners = mutableListOf<GridPreviewListener>()
+    var listeners = mutableListOf<GridPreviewListener>()
     private var lastVariant: GameVariant? = null
     private var lastGridCalculation: Deferred<Grid>? = null
 
@@ -35,7 +35,7 @@ class GridPreviewCalculationService(
         listeners.forEach { it.previewGridCreated(grid, false) }
     }
 
-    fun calculateGrid(
+    open fun calculateGrid(
         variant: GameVariant,
         scope: CoroutineScope,
     ) {