After deciding to begin work on a coin-operated version of
Spacewar, the pair, with assistance from Tuck's family, bought a PDP-11 and started working on a prototype. They spent a total of to build a single arcade machine for two players, like the original
Spacewar, deciding to price the game at ten cents per play or 25 cents for three games, with the winner of a match given a free game. They used a PDP-11/20 version of the PDP-11 (14,000), a
Hewlett-Packard 1300A Electrostatic Display (3,000), and spent the remainder on the coin acceptors, joysticks, wiring, and casing. Pitts build the computer hardware and handled the programming, while Tuck, a mechanical engineer, designed the
enclosing cabinet. The
display adapter for the monitor was built by Ted Panofsky, the coin acceptors were sourced from
jukebox manufacturer Rowe International, and the joysticks found at a military surplus store as remainders from
B-52 bomber controls. The code for the game was based on a version of
Spacewar running on a PDP-10 in the Stanford artificial intelligence lab, but modified with additional features. Pitts and Tuck renamed their product from
Spacewar to
Galaxy Game due to anti-war sentiment and founded a company called Mini-Computer Applications in June 1971 to operate the game as it neared completion. The development of the prototype machine took around three and a half months. By August, they were well into development and had gotten permission to place the machine at the Tresidder student union building at Stanford as a test site. It was then that they received a call from
Nolan Bushnell, who had heard of their project and wanted to show them his similar project he was working on. Bushnell had also played
Spacewar during the 1960s and wanted to make an arcade game version of it, but had gone in a different technological direction. He and
Ted Dabney had initially started with a US$4,000
Data General Nova computer which they thought would be powerful enough to run multiple simultaneous games of
Spacewar; when it turned out to not be, they had started investigating replacing the computer hardware with custom-built parts. They had soon discovered that while a general-purpose computer cheap enough for an arcade game would not be powerful enough to run enough games of
Spacewar to be profitable, a computer purpose-built for solely running one game could be made for as low as US$100. By August 1971 when Bushnell called Tuck and Pitts, he and Dabney had already displayed a prototype of their
Computer Space game in a bar near Stanford and had found a commercial manufacturer for the game in Nutting Associates. They were curious about what Tuck and Pitts had done to make a commercially competitive version of the game, but were relieved, though also somewhat disappointed, to find that they had not solved that problem yet. Tuck and Pitts, on the other hand, while impressed with Bushnell's hardware were not impressed with the game itself. They felt that
Computer Space, a single-player game without the central gravity well of the original game, was a pale imitation of
Spacewar, while their own
Galaxy Game was a superior adaptation of the game. In November 1971, the
Galaxy Game prototype debuted. The veneered walnut console, complete with seats for players, was located on the second floor of the building and connected to the PDP-11 in the attic by a 100-foot cable. In December, it was moved to a coffee shop on the first floor. It was very successful; Pitts later said that the machine attracted crowds of people "ten-deep" watching the players. They briefly attached a second monitor hanging above the console so that the watchers could more easily see the game. The low prices meant that they did not come close to making back the price of the PDP-11, but they were excited by the game's reception and had not intended the prototype to be profitable. As the initial
Galaxy Game prototype was displayed to the public a few months after the first
Computer Space prototype, it is believed to be the second video game to charge money to play. As a result of the reception to
Galaxy Game, Pitts and Tuck started work on an expanded prototype. For the second machine, they built a full blue fiberglass casing for the consoles, improved the quality of the joysticks with the help of a machine shop, and modified the computer with a newer display processor to support up to four games at once on different monitors—either multiple simultaneous separate games or up to four players playing the same game on two screens. They also placed the PDP-11 inside one of the consoles rather than in a separate location. While the original plan had been to work on driving down the development costs after the initial prototype, the popularity of the game convinced the pair to instead focus on making a better machine that could run multiple games to recoup the upfront investment. The new version was installed in a cafe in the student union building in June 1972, though with only two monitors due to space restrictions. The original
Galaxy Game prototype was displayed at several locations around the area, but was not as successful as it had been at the student union building. By the time the second prototype was completed the pair had spent US$65,000 on the project and had no feasible way of making up the cost with the machine or commercial prospects for a wider release. Pitts later explained that he and Tuck had been focused on the engineering and technical challenges of producing a faithful coin-operated
Spacewar game and paid little attention to the business side of the project; he felt that
Computer Space had been more commercially successful because Bushnell had focused more on the business side of his idea than the technical. ==Legacy==