diff --git a/TODO.md b/TODO.md
index af759e6..8dce45e 100644
--- a/TODO.md
+++ b/TODO.md
@@ -34,9 +34,7 @@ For screenshots:
 - add some custom daily puzzles
 
 - add link to sponsors?
-- relocate to new file:
-  - getWordValidityGrids
-  - countingGrid
 - just rename dispatch params to dispatcher everywhere
-- put arrayToGrid to common or to word-logic package
 - piecesOverlapQ should use getGridFromPieces
+
+- move common functions to word-logic package
diff --git a/src/logic/arrayToGrid.js b/src/common/arrayToGrid.js
similarity index 100%
rename from src/logic/arrayToGrid.js
rename to src/common/arrayToGrid.js
diff --git a/src/logic/arrayToGrid.test.js b/src/common/arrayToGrid.test.js
similarity index 100%
rename from src/logic/arrayToGrid.test.js
rename to src/common/arrayToGrid.test.js
diff --git a/src/components/Board.js b/src/components/Board.js
index f76a2be..9e40681 100644
--- a/src/components/Board.js
+++ b/src/components/Board.js
@@ -1,119 +1,8 @@
 import React from "react";
 import Piece from "./Piece";
 import DragShadow from "./DragShadow";
-import {getGridFromPieces} from "../logic/getGridFromPieces";
-import {isKnown} from "@skedwards88/word_logic";
-import {trie} from "../logic/trie";
-import {getWordsFromPieces} from "../logic/getWordsFromPieces";
-import {transposeGrid} from "@skedwards88/word_logic";
-
-// Returns a grid with the number of letters at each location in the grid
-export function countingGrid(height, width, pieces) {
-  let grid = Array(height)
-    .fill(undefined)
-    .map(() => Array(width).fill(0));
-
-  for (let piece of pieces) {
-    const letters = piece.letters;
-    let top = piece.boardTop ?? piece.dragGroupTop;
-    for (let rowIndex = 0; rowIndex < letters.length; rowIndex++) {
-      let left = piece.boardLeft ?? piece.dragGroupLeft;
-      for (let colIndex = 0; colIndex < letters[rowIndex].length; colIndex++) {
-        if (letters[rowIndex][colIndex]) {
-          grid[top][left]++;
-        }
-        left++;
-      }
-      top++;
-    }
-  }
-  return grid;
-}
-
-function getHorizontalValidityGrid({grid, originalWords}) {
-  // return a 2D array of bools indicating whether
-  // the position corresponds to a letter on the board
-  // that is part of a valid horizontal word
-  const height = grid.length;
-  const width = grid[0].length;
-
-  const horizontalValidityGrid = Array(height)
-    .fill(undefined)
-    .map(() => Array(width).fill(false));
-
-  for (const [rowIndex, row] of grid.entries()) {
-    let word = "";
-    let indexes = [];
-    for (const [columnIndex, letter] of row.entries()) {
-      if (letter != "") {
-        word += letter;
-        indexes.push(columnIndex);
-      } else {
-        if (word.length > 1) {
-          // If the word is one of the original words, always consider it valid (in case we updated the dictionary in the interim).
-          // Otherwise, check whether it is a word in the trie.
-          let isWord = originalWords.includes(word);
-          if (!isWord) {
-            ({isWord} = isKnown(word, trie));
-          }
-          if (isWord) {
-            indexes.forEach(
-              (index) => (horizontalValidityGrid[rowIndex][index] = true),
-            );
-          }
-        }
-        word = "";
-        indexes = [];
-      }
-    }
-    // Also end the word if we reach the end of the row
-    if (word.length > 1) {
-      // If the word is one of the original words, always consider it valid (in case we updated the dictionary in the interim).
-      // Otherwise, check whether it is a word in the trie.
-      let isWord = originalWords.includes(word);
-      if (!isWord) {
-        ({isWord} = isKnown(word, trie));
-      }
-      if (isWord) {
-        indexes.forEach(
-          (index) => (horizontalValidityGrid[rowIndex][index] = true),
-        );
-      }
-    }
-  }
-
-  return horizontalValidityGrid;
-}
-
-export function getWordValidityGrids({
-  pieces,
-  gridSize,
-  includeOriginalSolution = true,
-}) {
-  const originalWords = includeOriginalSolution
-    ? getWordsFromPieces({
-        pieces,
-        gridSize,
-        solution: true,
-      })
-    : [];
-
-  const grid = getGridFromPieces({pieces, gridSize, solution: false});
-
-  const horizontalValidityGrid = getHorizontalValidityGrid({
-    grid,
-    originalWords,
-  });
-
-  const transposedGrid = transposeGrid(grid);
-  const horizontalTransposedValidityGrid = getHorizontalValidityGrid({
-    grid: transposedGrid,
-    originalWords,
-  });
-  const verticalValidityGrid = transposeGrid(horizontalTransposedValidityGrid);
-
-  return [horizontalValidityGrid, verticalValidityGrid];
-}
+import {getLetterCountPerSquare} from "../logic/getLetterCountPerSquare";
+import {getWordValidityGrids} from "../logic/getWordValidityGrids";
 
 export default function Board({
   pieces,
@@ -131,7 +20,7 @@ export default function Board({
 
   const overlapGrid = customCreation
     ? undefined
-    : countingGrid(gridSize, gridSize, boardPieces);
+    : getLetterCountPerSquare(gridSize, gridSize, boardPieces);
 
   const [horizontalValidityGrid, verticalValidityGrid] = indicateValidity
     ? getWordValidityGrids({
@@ -160,7 +49,7 @@ export default function Board({
     const draggedPieces = pieces.filter((piece) =>
       dragPieceIDs.includes(piece.id),
     );
-    const grid = countingGrid(gridSize, gridSize, draggedPieces);
+    const grid = getLetterCountPerSquare(gridSize, gridSize, draggedPieces);
     dragShadow = (
       <DragShadow
         grid={grid}
diff --git a/src/components/Pool.js b/src/components/Pool.js
index a4c6a6a..f5c76c9 100644
--- a/src/components/Pool.js
+++ b/src/components/Pool.js
@@ -1,7 +1,7 @@
 import React from "react";
 import Piece from "./Piece";
 import DragShadow from "./DragShadow";
-import {countingGrid} from "./Board";
+import {getLetterCountPerSquare} from "../logic/getLetterCountPerSquare";
 
 export default function Pool({pieces, dragDestination, dispatchGameState}) {
   const poolPieces = pieces.filter((piece) => piece.poolIndex >= 0);
@@ -29,9 +29,11 @@ export default function Pool({pieces, dragDestination, dispatchGameState}) {
         <div className="pool-slot shadow" key={piece.id}>
           <DragShadow
             key={`shadow-piece-${piece.id}`}
-            grid={countingGrid(piece.letters.length, piece.letters[0].length, [
-              {...piece, dragGroupTop: 0, dragGroupLeft: 0},
-            ])}
+            grid={getLetterCountPerSquare(
+              piece.letters.length,
+              piece.letters[0].length,
+              [{...piece, dragGroupTop: 0, dragGroupLeft: 0}],
+            )}
           />
         </div>
       )),
diff --git a/src/logic/convertRepresentativeStringToGrid.js b/src/logic/convertRepresentativeStringToGrid.js
index 1993c63..7ab9b68 100644
--- a/src/logic/convertRepresentativeStringToGrid.js
+++ b/src/logic/convertRepresentativeStringToGrid.js
@@ -1,4 +1,4 @@
-import {arrayToGrid} from "./arrayToGrid";
+import {arrayToGrid} from "../common/arrayToGrid";
 import {cipherLetter} from "./cipherLetter";
 
 // Converts a string of letters and integers into a square grid of single letters and empty strings.
diff --git a/src/logic/getLetterCountPerSquare.js b/src/logic/getLetterCountPerSquare.js
new file mode 100644
index 0000000..64acfe3
--- /dev/null
+++ b/src/logic/getLetterCountPerSquare.js
@@ -0,0 +1,22 @@
+// Returns a grid with the number of letters at each location in the grid
+export function getLetterCountPerSquare(height, width, pieces) {
+  let grid = Array(height)
+    .fill(undefined)
+    .map(() => Array(width).fill(0));
+
+  for (let piece of pieces) {
+    const letters = piece.letters;
+    let top = piece.boardTop ?? piece.dragGroupTop;
+    for (let rowIndex = 0; rowIndex < letters.length; rowIndex++) {
+      let left = piece.boardLeft ?? piece.dragGroupLeft;
+      for (let colIndex = 0; colIndex < letters[rowIndex].length; colIndex++) {
+        if (letters[rowIndex][colIndex]) {
+          grid[top][left]++;
+        }
+        left++;
+      }
+      top++;
+    }
+  }
+  return grid;
+}
diff --git a/src/logic/getWordValidityGrids.js b/src/logic/getWordValidityGrids.js
new file mode 100644
index 0000000..71fe1f9
--- /dev/null
+++ b/src/logic/getWordValidityGrids.js
@@ -0,0 +1,90 @@
+import {getGridFromPieces} from "../logic/getGridFromPieces";
+import {getWordsFromPieces} from "../logic/getWordsFromPieces";
+import {transposeGrid} from "@skedwards88/word_logic";
+import {isKnown} from "@skedwards88/word_logic";
+import {trie} from "../logic/trie";
+
+function getHorizontalValidityGrid({grid, originalWords}) {
+  // return a 2D array of bools indicating whether
+  // the position corresponds to a letter on the board
+  // that is part of a valid horizontal word
+  const height = grid.length;
+  const width = grid[0].length;
+
+  const horizontalValidityGrid = Array(height)
+    .fill(undefined)
+    .map(() => Array(width).fill(false));
+
+  for (const [rowIndex, row] of grid.entries()) {
+    let word = "";
+    let indexes = [];
+    for (const [columnIndex, letter] of row.entries()) {
+      if (letter != "") {
+        word += letter;
+        indexes.push(columnIndex);
+      } else {
+        if (word.length > 1) {
+          // If the word is one of the original words, always consider it valid (in case we updated the dictionary in the interim).
+          // Otherwise, check whether it is a word in the trie.
+          let isWord = originalWords.includes(word);
+          if (!isWord) {
+            ({isWord} = isKnown(word, trie));
+          }
+          if (isWord) {
+            indexes.forEach(
+              (index) => (horizontalValidityGrid[rowIndex][index] = true),
+            );
+          }
+        }
+        word = "";
+        indexes = [];
+      }
+    }
+    // Also end the word if we reach the end of the row
+    if (word.length > 1) {
+      // If the word is one of the original words, always consider it valid (in case we updated the dictionary in the interim).
+      // Otherwise, check whether it is a word in the trie.
+      let isWord = originalWords.includes(word);
+      if (!isWord) {
+        ({isWord} = isKnown(word, trie));
+      }
+      if (isWord) {
+        indexes.forEach(
+          (index) => (horizontalValidityGrid[rowIndex][index] = true),
+        );
+      }
+    }
+  }
+
+  return horizontalValidityGrid;
+}
+
+export function getWordValidityGrids({
+  pieces,
+  gridSize,
+  includeOriginalSolution = true,
+}) {
+  const originalWords = includeOriginalSolution
+    ? getWordsFromPieces({
+        pieces,
+        gridSize,
+        solution: true,
+      })
+    : [];
+
+  const grid = getGridFromPieces({pieces, gridSize, solution: false});
+
+  const horizontalValidityGrid = getHorizontalValidityGrid({
+    grid,
+    originalWords,
+  });
+
+  const transposedGrid = transposeGrid(grid);
+  const horizontalTransposedValidityGrid = getHorizontalValidityGrid({
+    grid: transposedGrid,
+    originalWords,
+  });
+  const verticalValidityGrid = transposeGrid(horizontalTransposedValidityGrid);
+
+  return [horizontalValidityGrid, verticalValidityGrid];
+}