Rubik's Clock is a mechanical puzzle invented and patented by Christopher C. Wiggs and Christopher J. Taylor. The Hungarian sculptor and professor of architecture Ernő Rubik bought the patent from them to market the product under his name. It was first marketed in 1988.
Rubik's Clock is a two-sided puzzle, each side presenting nine clocks to the puzzler. There are four wheels, one at each corner of the puzzle, each allowing the corresponding corner clock to be rotated directly. (The corner clocks, unlike the other clocks, rotate on both sides of the puzzle simultaneously and can never be operated independently. Thus the puzzle contains only 14 independent clocks.)
There are also four buttons which span both sides of the puzzle; each button arranged such that if it is "in" on one side it is "out" on the other. The state of each button (in or out) determines whether the adjacent corner clock is mechanically connected to the three other adjacent clocks on the front side or on the back side: thus the configuration of the buttons determines which sets of clocks can be turned simultaneously by rotating a suitable wheel.
The aim of the puzzle is to set all nine clocks to 12 o'clock (straight up) on both sides of the puzzle simultaneously.
Since there are 14 independent clocks, with 12 settings each, there is a total of 14^12=1,283,918,464,548,864 possible combinations.
The world record for a single solve is 3.73 seconds, set by Nathaniel Berg of Sweden on 20 June 2015 at Danish Open 2015. The world record average of 5 (excluding fastest and slowest) is 5.23 seconds, set by Tairan Zhong (钟泰然) of China on 29 May 2017 at Zhuhai Open 2017.
- Patents EP0322085 (1989-06-28), JP1171588 (1989-07-06), GB2213739 (1989-08-23), US4869506 (1989-09-26)
- World Cube Association - Rubik's Clock Single Rankings
- World Cube Association - Rubik's Clock Average Rankings