Classic Reversi (Othello). Flank a line of your opponent's discs to flip them all to your colour — own the most discs when the board fills up. Play the CPU or a friend, right here in your browser.
How to play: click or tap any highlighted square, or use arrow keys to move the cursor and Enter/Space to place a disc. A move must trap at least one straight line of the opponent's discs between the disc you place and another of your own.