OXO was the first digital graphical game to run on a computer, and was rather simple to use the player played against the computer, with output displayed on the computer's 35×16-pixel cathode ray tube. The source code was short, yet played a perfect game of noughts and crosses.
This game provides examples of:
- Match-Three Game: You have to line three naughts or crosses up.
- Unwinnable by Design: The computer never loses.
- Ur-Example: Depending on how you define a Video Game, this may be the first one ever, if you consider 1947's Cathode Ray Tube Amusement Device too simple. The next possibility is Tennis For Two.