OXO (also known as Noughts and Crosses) is a tic-tac-toecomputer game made for the EDSAC computer in 1952. It was written by Alexander S. (Sandy) Douglas as an illustration for his Ph.D. thesis on human-computer interaction for the University of Cambridge. OXO was the first known (graphical) game to run on a computer. However, there is a patent dating from 1947–1948 that describes a missile simulation game utilizing a cathode ray tube.1
The player played against the computer, and output was displayed on the computer's 35×16 pixelcathode ray tube. The source code was short, yet it played a perfect game of noughts and crosses. OXO did not have widespread popularity because the EDSAC was a computer unique to Cambridge.
OXO consisted of a digital display system that showed a "pod" visual system like scoreboards at the Olympics. It is argued that OXO was the first video game ever made, predating even William Higinbotham's Tennis For Two from 1958.
^ Thomas T. Goldsmith Jr. and Estle Ray Mann filed a United States patent application on January 25, 1947 and U.S. Patent #2 455 992 issued on December 14, 1948.