Desdemona is an Othello/Reversi player 

Play takes place between two human players or against the computer. There are several levels of computer opponent, ranging from very simple to pretty smart. There is also a high score table, and a Replay function to allow moves to be undone or games restarted from different points. The application takes up around 300K of space, and runs on RISC OS 3.1 or later. A 256-colour or better display is recommended.