Nimatron

The reception of the machine during the fair was positive, with around 100,000 games of Nim played. After the fair it was moved to the Buhl Planetarium and Institute of Popular Science Building in Pittsburgh. Despite this success, Condon considered the Nimatron a failure, because he had designed and intended it to be solely a piece of entertainment for fair-goers, but within years of the exhibition programmable digital computers began to be produced around the world by other companies and groups that used some of the same principles around storing digital information. The Nimatron is considered one of the first electro-mechanical games and a precursor to computer games, but its direct impact on digital computers and computer games is minimal. It may, however, have inspired the Nimrod computer, which was demonstrated at the 1951 Festival of Britain playing Nim using banks of lightbulbs like the Nimatron eleven years prior.

Development

The 1939 New York World's Fair was held in April—October 1939 and April—October of 1940, featuring exhibits from countries and companies worldwide. A major exhibitor was the Westinghouse Electric Corporation, and during the break in the fair it was looking for new exhibits to add for the second season. Edward Condon, a nuclear physicist and pioneer of quantum mechanics and an Associate Director of Research at the company, proposed making a machine that could play Nim. In Nim, players take turns removing at least one object from a set of objects, with the goal of being the player who removes the last object; gameplay options can be modeled mathematically. In the version of the game Condon proposed using, there are multiple sets of objects, and on each turn the player can only remove objects from a single set. Condon, who claims to have come up with the idea while talking to another employee on his lunch break, knew that mathematically the model could be expressed with the same binary notation that was used in the circuits for Geiger counters. The proposal was not intended to showcase any particular technology, but only to serve as entertainment for the fair-goers. The result, named Nimatron, was an early non-programmable digital computer, as it could retain the state of the game in binary and respond according to which mechanical switches were flipped, though no changes could be made without physically modifying the machine.

The machine itself was designed and built by Gerald L. Tawney and Willard A. Derr, who worked in the relay division of Westinghouse. Although electronic vacuum tubes were faster than electro-mechanical relays at processing information, the machine was designed and built with electro-mechanical relays as vacuum tubes were less robust and speed was not an issue. Even with relays, the machine was considered too fast; it could still make its turn in milliseconds as opposed to the microseconds it would have taken with vacuum tubes, which was felt to be demoralizing to players. The team added a delay relay to the game of a couple seconds to make it appear that the machine was thinking about the move to make instead of the physical algorithm nearly instantly responding. The state of the game was represented with four columns of seven lights; on the player's turn they decided on a column to take lights from and pressed a button one or more times to turn out lights in that column, then pressed another to give the machine a turn. The set of lights were displayed on the front of the machine, as well as on four sides of a cube above the machine to allow spectators to follow the game. If the player won, the machine produced a token with the inscription "Nim Champ". The machine, described by Popular Mechanics as having 116 relays and over two miles of copper wire, and by The New York Times as being a robot eight feet tall and three feet wide, encased in a metal box, weighed over a metric ton. Westinghouse, on behalf of Condon, Tawney, and Derr, filed a patent application with the United States on April 26, 1940 and obtained it on September 24, 1940.