Reversi (also known as Othello), is a board game for two players,
played on a grid of 64 squares. The game begins with each player having two stones.
The players alternate turns, each adding an additional stone to the board.
A valid move must capture at least one of the opponent's stones. This is done by
surrounding it, either vertically, horizontally, or diagonally (or a combination of all three).
When this occurs, the opponent's stones that you have surround become yours.
The turn then passes to your opponent, who tries to take as many of your stones as he can.
Play continues until either one player loses all their stones, or until the entire board
if filled. Whoever ends up owning the most stones at the end of the game wins.
