Rubik's Clock
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. The method to do so is to start by constructing a cross on both sides (at 12 o’clock) and then solving the corner clocks. The Rubik’s clock is listed as one of the 17 WCA events, with records for fastest time to solve one puzzle, and the fastest average time to solve 5 puzzles (discarding the slowest and fastest times). Combinations
Since there are 14 independent clocks, with 12 settings each, there are a total of =1,283,918,464,548,864 possible combinations for the clock faces. This does not count for the number of pin positions. Notation 
The puzzle is oriented with 12 o'clock on top, and either side in front. The following moves can be made:

Pin movements:

 UR (top-right): Move the top-right pin up. DR (bottom-right): Move the bottom-right pin up. DL (bottom-left): Move the bottom-left pin up. UL (top-left): Move the top-left pin up. U (both top): Move both top pins up. R (both right): Move both right pins up. D (both bottom): Move both bottom pins up. L (both left): Move both left pins up. ALL (all): Move all pins up. Wheel movements:

 X+ (X clockwise turns): Turn a wheel next to an up-position pin clockwise X times, then move all pins down. X- (X counter-clockwise turns): Turn a wheel next to an up-position pin counter-clockwise X times, then move all pins down. Puzzle rotation:

 y2: Turn around the puzzle so that 12 o'clock stays on top, and then move all pins down. Records
The world record for a single solve is 2.61 seconds, set by Tommy Cherry of United States on 17 June 2023 at "CubingUSA Mid-Atlantic Championship 2023". The world record average of 5 (excluding fastest and slowest) is 3.50 seconds, set by Tommy Cherry of the United States on 30 July 2023 at the CubingUSA Nationals 2023 in David L. Lawrence Convention Center, Pittsburgh, Pennsylvania with the times of 3.29, 3.86, (3.27), 3.36, and (DNF) seconds. Top 5 solvers by single solve

Top 5 solvers by Olympic average of 5 solves

References

External links
 Rubik's Clock Solution An illustrated description of the solution. Unofficial Records Speedsolving.com's page of unofficial records for many puzzles including Rubik's Clock
 Real Genius Computer game implementation of Rubik's Clock for the Commodore Amiga, released in 1989
 https://www.worldcubeassociation.org/results/rankings/clock/average
 https://www.worldcubeassociation.org/results/rankings/clock/single?show=100+persons

Mechanical puzzles
Combination puzzles
1988 works
1988 introductions
1980s toys