In 1971, Mike Mayfield, then a senior in high school, frequented a computer lab at the University of California, Irvine while teaching himself how to program. The lab operated both a SDS Sigma 7 and a DEC PDP-10 mainframe computer. The PDP-10 hosted a copy of "Spacewar!", a multiplayer space combat video game developed in 1962 in the early history of video games. Mayfield had gained illicit access to the Sigma 7 at the lab and wanted to create his own version of the game for the system. "Spacewar!" required a vector graphics display, however, and the Sigma 7 only had access to a non-graphical Teletype Model 33 ASR teleprinter.