shinuza

Reversi is a board game for two players: the White and the Black players. 

The board contains 8x8 squares, like a chess board.
The players place black or white pieces (the stones) onto
the board, one piece per square. 

Whenever one or several white pieces are "sandwiched" between 2 black pieces,
they are "fliped": they change color from white to black, and vice-versa.
Sandwiching can happen vertically, horizontally of diagonally.