Make your board out of 1x1's, and paint it black. Set events on each brick so that it says;
0 (checked) OnActivate > Self > Setcolor > White
1 (unchecked) OnActivate > Self > Setcolor > Black
2 (checked) OnActivate > Self > Toggleeventenabled > 0 1
Then, when you click it, it will become white. If you click again, it will become black again.