diff --git a/gameOfLife.py b/gameOfLife.py
index 4db1b8d..44578f0 100644
--- a/gameOfLife.py
+++ b/gameOfLife.py
@@ -73,6 +73,7 @@ for frame in range(500):
 
     # calculate next step
     gameBoardNextStep = []
+    lastGameBoard = gameBoard
     for rowIndex in range(HEIGHT):
         newRow = []
         for colIndex in range(WIDTH):