In the British Isles, Europe and North America the Tic-Tac-Toe pattern is often drawn on paper.  Two players take turns marking their symbol {an X or an O} in the squares formed by the intersecting lines.  The aim of each player is to make a row of three of his/her  symbols. A winning pattern follows one of three forms: vertical, horizontal, or diagonal.

It is said that only the player who goes first can win, and  only then if the second player makes a mistake.  If the second player makes no strategy blunders the game will end in a tie, called a "Cats Game".

This implementation allows the human player to try his or her skill against the computer.  Options include selection of symbol, and a selection that limits the computer to a less than perfect strategy.  This gives the human a chance to win.

Click here for a discussion of game history and strategy.