Make rows and columns to win blackstars which will serve you as joker.
The more you advance in levels, the more the difficulty increases, the more you will need blackstars.
Try to reach the ultimate level No. 28 (but do not dreaming!).
To put a tile in a box, all adjacent boxes need to have a common property with the tile (same form or same color).
To earn a blackstar, complete a row or column.
To finish a level, cover at least once each box.