One of the yellow ones

Last week my father bought a new mobile phone, and gave me his older phone, a Siemens M35i (one of those yellow ones), so that I could finally get rid of my Ericsson 'the brick' 688. The Siemens has a few games, including the horrible, imoral, shameless and fun Minesweeper ("with Microsoft's compliments", it says). However, it's a game called Reversi that I have become addicted to. In a nutshell, it's a version of the Othello table-top strategy game, and it has slowly started to become a time-sink, as I play it even while at home with work to do. 'Reversi Anonymous', anyone?