Combine 2 of the same mahjong stones to remove them from the playing field. You only can use free stones. A free stone is not covered by another stone and at least 1 side (left or right) is open.
Remove the lines from the falling blocks. Lines will be removed if a line has a length of 3 or more blocks. A block without any lines will be removed from the playing field. Touch a block to rotate the lines and touch a column to change position.