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
Nurikabe (puzzle) Nurikabe (puzzle) Nurikabe (hiragana: ぬりかべ) is a binary determination puzzle named for Nurikabe, an invisible wall in Japanese folklore that blocks roads and delays foot travel. Nurikabe was apparently invented and named by Nikoli; other names (and attempts at localization) for the puzzle include "Cell Structure" and "Islands in the Stream". The puzzle is played on a typically rectangular grid of cells, some of which contain numbers. Cells are initially of unknown color, but can only be black or white. Two same-color cells are considered "connected" if they are adjacent vertically or horizontally, but not diagonally. Connected white cells form