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Pyraminx

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Pyraminx in its solved state

The Pyraminx (/ˈpɪrəmɪŋks/) is a regular tetrahedron puzzle in the style of Rubik's Cube. It was made and patented by Uwe Mèffert after the original 3 layered Rubik's Cube by Ernő Rubik, and introduced by Tomy Toys of Japan (then the 3rd largest toy company in the world) in 1981.[1]

Optimal solutions

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The maximum number of twists required to solve the Pyraminx is 11. There are 933,120 different positions (disregarding the trivial rotation of the tips), a number that is sufficiently small to allow a computer search for optimal solutions. The table below summarizes the result of such a search, stating the number p of positions that require n twists to solve the Pyraminx:[2]

n 0 1 2 3 4 5 6 7 8 9 10 11
p 1 8 48 288 1728 9896 51808 220111 480467 166276 2457 32

Records

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Andreas Pung solving a Pyraminx at a competition

The world record single solve is 0.73 seconds, set by Simon Kellum of the United States at Middleton Meetup Thursday 2023. The world record average of five solves (excluding fastest and slowest) is 1.27 seconds, set by Lingkun Jiang of China at Deqing Small Cubes Summer 2024.[3]

Top 5 solvers by single solve[4]

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Number Name Fastest solve Competition
1. United States Simon Kellum 0.73s United States Middleton Meetup Thursday 2023
2. United States Elijah Brown 0.75s United States Berkeley Winter A 2023
3. New Zealand Connor Johnson 0.82s New Zealand Groundhog Day in Somerfield 2024
4. New Zealand Jasper Murray 0.83s New Zealand Groundhog Day in Somerfield 2024
5. Slovakia Jakub Drobný 0.84s Slovakia Banská Bystrica Open 2024

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

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Number Name Fastest average Competition Times
1. China Lingkun Jiang 1.27s China Deqing Small Cubes Summer 2024 (1.43), 1.22, (1.18), 1.21, 1.39
2. United States Ezra Shere 1.45s United States Washtenaw Fast 'n Late Fall 2023 (1.82), 1.42, 1.42, 1.50, (1.38)
3. New Zealand Jasper Murray 1.47s New Zealand Lyttleton Spring 2023 1.64, 1.60, (1.82), (1.08), 1.18
4. New Zealand Elyas Eyou 1.48s New Zealand New Zealand Cubing Decathlon 2024 1.50, 1.42, 1.51, (2.83), (1.36)
4. Australia Sebastian Lee 1.48s Australia Kogarah Cube Day Saturday 2024 1.37, (1.76), 1.67, 1.40, (1.34)

Methods

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There are many methods for solving a Pyraminx. They can be split up into two main groups.

1) V First Methods - In these methods, two or three edges are solved first, and a set of algorithms, also called LL (last layer) algorithms, are used to solve the remainder of the puzzle.

2) Top First Methods- In these methods, three edges around a center piece are solved first, and the remainder of the puzzle is solved using a set of algorithms.

Common V first methods-

a) Layer by Layer - In this method, a face with all edges permuted is solved, and then the remaining puzzle is solved by a single algorithm from a set of 5.

b) Algorithmic L4E and Intuitive L4E - L4E or last 4 edges is somewhat similar to Layer by Layer. The only difference is that only two edges are solved around three centers. Both of these methods solve the last four edges in the same step, hence the name. The difference is that Intuitive L4E requires a lot of visualization and "intuition" to solve the last four edges while algorithmic L4E uses algorithms. Algorithmic L4E is generally used more at higher levels, although there are very fast Intuitive L4E users. It is also easy to transition between Intuitive L4E and Algorithmic L4E.

Common top first methods-

a) One Flip - This method uses two edges around one center solved and the third edge flipped. There are a total of six cases after this step, for which algorithms are memorized and executed. The third step involves using a common set of algorithms for all top first methods, also called Keyhole last layer, which involves 5 algorithms, four of them being the mirrors of each other.

b) Keyhole - This method uses two edges in the right place around one center, and the third edge placed elsewhere on the puzzle. The centers of the fourth color are then solved using the slot formed by the non-permuted edge. The last step is solved using Keyhole last layer algorithms.

c) OKA - In this method, one edge is oriented around two edges in the wrong place, but one of the edges that is in the wrong place belongs to the block itself. The last edge is found on the bottom layer, and a very simple algorithm is executed to get it in the right place, followed by keyhole last layer algorithms.

Some other common top first methods are WO and Nutella.

Many Pyraminx speedsolvers learn several methods, particularly top-first methods, and use the method that is best for the given solve.[6]

There is no consensus among pyraminx speedsolvers regarding whether top-first or v-first methods are faster, although v-first is more common in the present day.

Variations

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A solved Tetraminx.

There are several variations of the puzzle. The simplest, Tetraminx, is equivalent to the (3x) Pyraminx but without the tips (see photo), resembling a truncated tetrahedron. There also exist "higher-order" versions, such as the 4x Master Pyraminx (see photos) and the 5x Professor's Pyraminx.

A basic pattern on a Master Pyraminx
A solved Master Pyraminx

The Master Pyraminx has 4 layers and 16 triangles-per-face (compared to 3 layers and 9 triangles-per-face of the original), and is based on the Skewb Diamond mechanism. This version has about 2.6817 × 1015 combinations.[7][8] The Master Pyraminx has

  • 4 "tips" (same as the original Pyraminx)
  • 4 "middle axials" (same as the original Pyraminx)
  • 4 "centers" (similar to Rubik's Cube, none in the original Pyraminx)
  • 6 "inner edges" (similar to Rubik's Cube, none in the original Pyraminx)
  • 12 "outer edges" (2-times more than the 6 of the original Pyraminx)

In summary, the Master Pyraminx has 30 "manipulable" pieces. However, like the original, 8 of the pieces (the tips and middle axials) are fixed in position (relative to each other) and can only be rotated in place. Also, the 4 centers are fixed in position and can only rotate (like the Rubik's Cube). So there are only 18 (30-8-4) "truly movable" pieces; since this is 10% fewer than the 20 "truly movable" pieces of the Rubik's Cube, it should be no surprise that the Master Pyraminx has about 10,000-times fewer combinations than a Rubik's Cube (43 quintilion in the short scale or 43 trilion in the long scale). The Master Pyraminx can be solved in numerous ways: one is layer by layer like the original one or reducing it to a Jing pyraminx.[9]

Reviews

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See also

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References

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  1. ^ "Puzzles, Pyraminx, Twisting puzzles, Kokonotsu-Super-Sudoku, Megaminx, 5x5x5 cube".
  2. ^ Pyraminx - Jaap's Puzzle Page
  3. ^ "Pyraminx - Official World Records (Single and Average)". World Cube Association. Retrieved 7 July 2023.
  4. ^ World Cube Association Official Pyraminx Ranking Single
  5. ^ World Cube Association Official Pyraminx Ranking Average
  6. ^ World Cube Association - Drew Brads results.
  7. ^ "Full List of Puzzles". gandreas software. Archived from the original on 28 April 2016. Retrieved 31 December 2016.
  8. ^ "Notes on Twisty Puzzles". Michael Gottlieb. Retrieved 31 December 2016.
  9. ^ Martin Schönert "Analyzing Rubik's Cube with GAP": the permutation group of Rubik's Cube is examined with GAP computer algebra system
  10. ^ "GAMES Magazine #29". May 1982.
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