

William Keister (19071997) was a pioneer in switching theory and design at Bell Labs. When he retired in 1972, he was director of Bell Labs' Computing Technology Center at Holmdel, New Jersey.
Mr. Keister's interest in puzzles began as a boy in Montgomery, Alabama, where he designed puzzles when he wasn't busy building crystal radio sets and writing poetry. In the late 1930s and 40s, when engineers were only beginning to appreciate the logic that would later form the basis of computers, Mr. Keister began to look at logic puzzles and how they could be solved through formal design methods. "At the time," he says, "we knew that computing machines could add, multiply, and divide, but it was not so apparent that they could be programmed to perform logic."
Mr. Keister began working in his spare time to prove that puzzles could be solved through logic design. One day he raided Bell Labs' stock room, gathering up pushbuttons, electronic relays, and light bulbs to build an electronic version of the Chinese Ring Puzzle. After a few hours work, he realized he had wired it up wrong, but studying what he had done he also realized that he had stumbled onto a whole series of binary code sequence puzzles, of which the famous Chinese Ring Puzzle was just one variation. He went on to sketch out a whole series of logic puzzles and show how they could be solved mathematically with Boolean algebra, a precursor to today's computer languages.
