It's possible to be to change 1 block by a tap and destroy everything by a chain in a block on the board. It's the purpose of a game to find the block.
* A circular block of red and blue is arranged in a field.
* When a tap blocks, a red circle changes to a blue circle and a blue circle changes to a red circle..
* When more than 3 of the same block connects with vertical, horizontal that goes off.
* There is one block where all blocks go off in a field. This game finds that.