This game is what is called a color concentration.
Tap two black squares to find ones of the same color.
You can choose the number of squares.
There are 4 types: 4x4, 6x6, 8x8, 10x10.
Naturally, the larger the number, the more difficult it is.
You can set the number of squares on a side on the first screen by the slider: 4, 6, 8, 10.
If you tap "START" button, then you can start this game.
Tap two black squares.
If they have the same color, then tap other two black squares.
Otherwise tap "UNDO", and do it over.
If you are completed and want to restart, then tap "START".
If you want to go back the first screen, then tap your device back button.