Speedcubing are also different shapes of the famous puzzles, including Pyraminx, Megaminx, Skewb, and Square-1. The Rubik's Cube was invented in 1974 by Hungarian professor of architecture, Ernő Rubik. A widespread international interest in the cube began in 1980, which soon developed into a global craze. On June 5, 1982, the first world championship was held in Budapest, Hungary. 19 people competed in the event and the American Minh Thai won with a single solve time of 22.95 seconds. Other notable attendees include Jessica Fridrich and Lars Petrus, two people who would later be influential in the development of solving methods
Hat puzzle hat color. In common with many puzzles of this type, the solution relies upon the assumption that all participants are totally rational and intelligent enough to make the appropriate deductions. After solving this puzzle, some insight into the nature of communication can be gained by pondering whether the meaningful silence of prisoner D violates the "No communication" rule (given that communication is usually defined as the "transfer of information"). In a variant of this puzzle, the prisoners know that there are 3 hats of one color and only 1 hat of another (e.g. 3 black and 1 white), and the