Reversi

Place a disc so it surrounds one or more opposing discs in a straight line between your new disc and an existing one. Every surrounded line flips to your color. If you have no legal move, your turn is skipped automatically. Play ends when neither player can move. Whoever has more discs wins; equal counts draw.

Online rooms wait for all players. Everyone must agree to a rematch. Leaving or disconnecting clears that online board.