A simple variation of the classic game of Mahjongg (also known as Shanghai). Each of the 40 levels consist of rows and piles of tiles, patterned with symbols such as butterflies and masks. Pair them up within the time limit to move on a level. The difficulty is that a tile can only be moved if it has no tile on top of it, and a gap either to the left or right (or both). Careful planning ahead is required if all tiles are to be cleared.