Penim is a variant of Nim, played with five kinds of pieces: 11 small circles, 9 short rounded rectangles, 7 small squares, 5 long rounded rectangles, and 3 large squares. The pieces are organized into heaps and the players take turns removing the pieces until none are left. The last player to remove a piece wins the game. The rules provide for varying degrees of difficulty, with different combinations of the pieces being used and different rules for who can take what piece.