It is a game to erase all the croskets.
If you touch Crosket, you can erase all the croskets connected in the same color. At this time, it can not be erased without the same color crotch on the top, bottom, left, and right. If you can not erase it, a crotch will appear.
The game is over when all cross marks have been erased. The time until then is registered as a grade.
There are 3 difficulties.