In 1952, University of Cambridge student Alexander Sandy Douglas was working towards earning his Ph.D. His thesis focused on human-computer interactions and he needed an example to prove his theories. At that time Cambridge was home to the very first stored-program computer, the Electronic Delay Storage Automatic Calculator (EDSAC). This gave Douglas the perfect opportunity to prove his findings by programming the code for a simple game where a player can compete against the computer.

The actual program for the game was read off of Punched Tape (aka Input Tape), a strip of paper with numerous holes punched into it. The placement and number of holes would be read as code by the EDSAC, and translated into an oscilloscope's cathode-ray tube readout display as an interactive game.

Douglas' project was a success and became the very first video game and graphical computer game, but it was also one of the very first (albeit primitive) applications of true artificial intelligence. The computer's moves in reaction to the player move were not random or pre-determined but entirely made at the computer's discretion. OXO is often overlooked for its accomplishments in artificial intelligence as the study of AI didn't become a valid science until 1958 when scientist John McCarthy coined the term.

Source: Livewire