Tetris is a classical 2-D tile matching game. In Tetris, players must complete lines by moving differently shaped pieces (tetrominoes), which descend onto the playing field. The completed lines disappear and grant the player points, and the player can proceed to fill the vacated spaces. The game ends when the playing field is filled. The longer the player can delay this inevitable outcome, the higher their score will be and the speed of the tetrominoes increses as the score increases.