Reversi (also known as Othello) on a green felt board, you against the machine. Place a disc so it traps a straight line of your opponent's discs between the one you just played and another of yours, and every disc in that line flips to your colour. You must outflank at least one disc on every move. When neither side can move, whoever owns more of the board wins.
Pick your colour and how hard the computer plays — from a gentle Easy up to an Expert that searches several moves ahead and solves the endgame exactly. Corners can never be flipped, so they're worth everything; the squares next to them are traps. Go Fullscreen for a board that fills the screen.
Click a highlighted square to play there. Legal moves are dotted; if you can't move, your turn is skipped automatically. Difficulty and colour are remembered on this device, along with your record. A from-scratch Reversi with an alpha–beta search opponent.