Two boards look the same, but four things are different. Tap a difference on either board to mark it. Stuck? The Show me button reveals them.
Scan row by row instead of looking at the whole board, and compare the same position on each board. Differences often hide at the edges.
Each board is generated fresh, so you will not see the same one twice.
Frequently asked questions
How many differences are there?
Four on every board.
Can I give up?
Yes. Press Show me to reveal them.
Is there a timer?
Yes, your time is shown when you finish.