Nintendo tumbler puzzle Nintendo tumbler puzzle The Nintendo tumbler puzzle, also known as the "Ten Billion Barrel" in English and originally in Japanese, is a mathematical puzzle in the style of Rubik's Cube. It was invented by Gunpei Yokoi of Nintendo in 1980 and was covered by (until the patent expired in March 1995 due to non-payment of a maintenance fee). It consists of a "cylinder" of transparent plastic divided into six levels, together with a black plastic "frame". The frame consists of upper and lower discs that are joined together through the middle of the cylinder. The top and bottom levels of
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