diff --git a/js/sudoku_builder.js b/js/sudoku_builder.js
index deab037..30329eb 100644
--- a/js/sudoku_builder.js
+++ b/js/sudoku_builder.js
@@ -16,7 +16,6 @@ class GridShape {
   constructor(gridSize, boxWidth, boxHeight) {
     this.boxWidth = boxWidth;
     this.boxHeight = boxHeight;
-    this.boxSize = boxWidth;
     this.gridSize = gridSize;
     this.numValues = gridSize;
     this.numCells = gridSize * gridSize;