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
-gry puzzle the answer "gry," an obsolete unit of measure invented by John Locke. It is unclear whether this was the answer given on the Grant show, or what the precise wording had been. By fall 1975 the puzzle had reached the Delaware Valley, again apparently by radio, by which time the puzzle seems to have mutated to a form in which the missing word is an adjective that describes the state of the world. The puzzle has had occasional bouts of popularity: after its initial popularity in 1975, it was popular in 1978, then again in 1995–1996. The most credible report