1977, Jim Guyton, a staff member at Xerox's Palo Alto Research Center (PARC), and Mike Wahrman, who worked at RAND Corporation, rewrote Maze for Xerox Alto computers, which could communicate with each other directly using the nascent ethernet networking protocol. Wahrman had played the game at MIT in 1976 while he and Guyton worked at RAND Corporation, which he enthusiastically described to Guyton using the name "Mazewar". After Guyton moved to Xerox, the pair felt that the game would be suited to the Alto and could be improved on there, and Wahrman got copies of the PDP-10 and PDS-1 code. The pair spent the next year working on the game, which has been inconsistently remembered as Mazewar, MazeWar, Maze War, and Maze Wars. They adapted the graphics from the vector displays of the PDS-1 to the raster displays of the Alto, added the top-down display of the maze and the player's position in it to always be below the first-person view, and changed the networking code to handle multiple systems talking directly to each other without a central PDP-10 server. They rewrote the game entirely in the Mesa programming language and were assisted by several other Xerox employees, including Steven Hayes, Bill Verplank, Jim Sandman, and Bruce Malasky. The text representation of other players was replaced with a large eyeball drawn by Verplank. The game was an immediate hit around the office, and within a few weeks it had spread to other Xerox locations. Eventually, it migrated to MIT, Stanford, and Carnegie Mellon University, which were some of the few non-Xerox locations that owned Xerox Alto computers. Guyton maintained the game for another six months before leaving Xerox for RAND. In 1981, Xerox commercially released a modified version of the Alto as the Xerox Star, and the source code to Mazewar proliferated after it, in turn inspiring further versions of Maze. Legacy Maze is believed to be the first 3D first-person game ever made. It is likely also the earliest example of what was later termed the first-person shooter genre; prior confusion over the development timeline of the game has led to it being considered, along with Spasim, an early 1974 space flight simulation game by Jim Bowery, to be one of the "joint ancestors" of the genre. It has additionally been credited with a variety of other firsts, such as level editing due to Lebling's editor, observer mode and