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Rubik's Clock

From Wikipedia, the free encyclopedia
The front face of a solved original Rubik's clock

The Rubik's Clock is a mechanical puzzle invented and patented by Christopher C. Wiggs and Christopher J. Taylor.[1] 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.

The Rubik's Clock is a two-sided puzzle, each side presenting nine clocks to the puzzler. There are four dials, 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 pins which span both sides of the puzzle; each pin arranged such that if it is "in" on one side, it is "out" on the other. The state of each pin (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 pins determines which sets of clocks can be turned simultaneously by rotating a suitable dial.

The aim of the puzzle is to set all nine clocks to 12 o'clock (straight up) on both sides of the puzzle simultaneously. A method to do so is to start by constructing a cross on both sides (at 12 o’clock) and then solving the corner clocks individually.

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). The puzzle is unique in the WCA in that it is the only puzzle for which viable speedsolving methods have been devised that always solve it in God's number moves (14 for the clock) or less; an example is "7-Simul", which involves performing seven pairs of moves on the front and back of the clock simultaneously and requires mental calculation from the puzzle's initial position to determine some moves.

Combinations

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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

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The puzzle is oriented with 12 o'clock on top, and either side in front. The following moves can be made:[2]

Pin movements:

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  • 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:

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

Puzzle rotation:

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  • y2: Turn around the puzzle so that 12 o'clock stays on top, and then move all pins down.

Records

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The world record for single solve is held by Brendyn Dunagan of the United States with a time of 1.97 seconds, set at La La Land 2024. The world record for Olympic average of five solves is held by Volodymyr Kapustianskyi of Ukraine with an average of 2.39 seconds, set at Grand Forks 2024.

Top 10 solvers by single solve[3]

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Name Result Competition
United States Brendyn Dunagan 1.97s United States La La Land 2024
Ukraine Volodymyr Kapustianskyi 2.15s United States Cubing in Oak Creek 2024
New Zealand Lachlan Gibson 2.16s New Zealand NZ Cubing Decathlon 2024
Norway Niklas Aasen Eliasson 2.25s Sweden Vännäs & Friends 2024
United States Jaidon Poraminthara Lin 2.27s United States UCSB Cubing 2024
United States Carter Thomas 2.29s United States Pyraminx in Pewaukee 2024
Australia Lachlan Adams-Romyn 2.30s Australia Queensland Open 2024
Poland Antoni Stojek 2.31s Poland Polish Championship 2024
Poland Eryk Kasperek Poland No Triangle in Rzeszów 2024
Russia Anatolii Turenko 2.33s Malaysia Rubik's WCA Asian Championship 2024

Top 11 solvers by Olympic average of 5 solves[4]

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Name Average Competition Times
Ukraine Volodymyr Kapustianskyi 2.39s United States Grand Forks 2024 (2.96) 2.46 (2.24) 2.29 2.43
Poland Eryk Kasperek 2.52s Poland Cube4fun Lublin on WEII 2024 2.44 (3.36) 2.59 (2.40) 2.52
New Zealand Lachlan Gibson 2.64s New Zealand Hasty Hastings 2024 (7.67) 3.17 2.42 2.32 (2.17)
United States Brendyn Dunagan 2.69s United States UCSB Cubing 2024 2.92 (2.04) 2.62 (2.95) 2.52
United States Carter Thomas 2.82s United States Pyraminx in Pewaukee 2024 (4.77) (2.45) 3.52 2.47 2.46
Norway Niklas Aasen Eliasson 2.93s Sweden 24 Hours in Åker 2024 3.05 (3.98) 2.98 2.76 (2.70)
United Kingdom Caleb Wolf Dunn 3.00s United Kingdom Rubik's UK Championship 2024 (2.70) 2.88 (4.18) 3.04 3.07
United Kingdom Danny Morgan 3.04s United Kingdom Stevenage October 2024 (3.42) 2.96 2.84 3.31 (2.70)
United States Greyson James 3.06s United States Indiana Championship 2024 3.16 2.97 (3.87) 3.04 (2.90)
United States Alessandro Diomampo 3.07s United States UCSB Cubing 2024 3.09 (6.18) (2.86) 3.02 3.10
Australia Lachlan Adams-Romyn Australia Chilling in Toowoomba 2024 2.75 (3.71) 3.32 3.13 (2.65)

References

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  1. ^ Patents EP0322085 (1989-06-28), JP1171588 (1989-07-06), GB2213739 (1989-08-23), US4869506 (1989-09-26)
  2. ^ "WCA Regulations | World Cube Association". www.worldcubeassociation.org. February 1, 2023. Retrieved 2023-04-24.
  3. ^ World Cube Association Official Clock Rankings - Single
  4. ^ World Cube Association Official Clock Rankings - Average
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