Larry D. Nichols Larry D. Nichols Larry D. Nichols, born 1939 in the United States, is a puzzle designer. He grew up in Xenia, Ohio, and studied chemistry at DePauw University in Greencastle, Indiana, before moving to Massachusetts to attend Harvard Graduate School. He is best known for the invention of mechanical puzzles including 'The Nichols Cube Puzzle' (1974), patent US365520. He has lived with his wife Karen in Arlington, Massachusetts since 1959. In 1957, 17 years before Dr. Rubik’s invention popularly known as the “Rubik's Cube”, Dr. Nichols conceived of a twist cube puzzle with six colored faces. It was a 2×2×2
Missing Link (puzzle) one row to another, up and down. There are 15 tiles and a gap, giving a maximum of 16! arrangements. However, the middle tiles of each four-tile chain are identical, and each position is equivalent to seven other positions obtained by rotating the entire puzzle (about its axis or upside-down), reducing the number of arrangements to 16! / 8 / 8 = 326,918,592,000. If the three long chains are also considered interchangeable, then the number of arrangements is further reduced to 16! / 8 / 8 / 6 = 54,486,432,000. Missing Link (puzzle) Missing Link is a mechanical puzzle invented