Mahjong solitaire is a solitaire matching game that uses a set of Mahjong tiles rather than cars. It is also known as Shanghai solitaire, electronic or computerized mahjong, MahJong solitaire, solitaire Mahjong and, erroneously, as Mahjong. The tiles come from the four-player game popular in East Asia known as Mahjong. The 144 tiles are arranged in a special four-layer pattern with their faces upwards. A tile is said to be open or exposed if it can be moved either left or right without disturbing other tiles. The goal is to match open pairs of identical tiles and remove them from the board, exposing the tiles under them for play. The game is finished when all pairs of tiles have been removed from the board or when there are no exposed pairs remaining.