[ introduction | index ]
Click an empty square to make your move. To scroll the board, drag with the right mouse button (Windows or Unix) or with the command key down (Macintosh). In human vs. computer mode you play against the computer. Switch to human vs. human if you want to play with a friend.
Once you get good at torus tic-tac-toe, try switching to a Klein bottle. Tic-tac-toe on a Klein bottle can be tricky - if the computer thinks it (or you!) has won and you don't understand why, try scrolling the board. You might also want to review the introduction to the Klein bottle.