It is a learning game playing with addition and subtraction.
If you set the number of green circles to be the same as the stage number, you can go to the next stage.
It becomes a failure when it becomes 0.
The light blue circle subtracts, and the pink circle adds.
It will clear up to that point as blue and pink circles disappear in a certain row!
Even if the circle is gone, the game is over.
If you move your finger on the screen without releasing your finger from the tapped location,
I will make a movement mixed with the direction of the difference and physical behavior.
Moving with a little null null, since there is gravity, going down is faster than going up.