 | This article relies largely or entirely on a single source .(August 2019) |
 | |
| Type | Puzzle |
|---|---|
| Inventor(s) | Adam Alexander |
| Company | Ideal Toy Company |
| Country | United States |
| Availability | 1982–present |
Alexander's Star is a puzzle similar to the Rubik's Cube, in the shape of a great dodecahedron.
Alexander's Star was invented by Adam Alexander, an American mathematician, in 1982. It was patented on 26 March 1985, with US patent number 4,506,891, and sold by the Ideal Toy Company. It came in two varieties: painted surfaces or stickers. Since the design of the puzzle practically forces the stickers to peel with continual use, the painted variety is likely a later edition.
The puzzle has 30 moving pieces, which rotate in star-shaped groups of five around its outermost vertices. The purpose of the puzzle is to rearrange the moving pieces so that each star is surrounded by five faces of the same color, and opposite stars are surrounded by the same color. This is equivalent to solving just the edges of a six-color Megaminx. The puzzle is solved when each pair of parallel planes is made up of only one colour. To see a plane, however, one has to look "past" the five pieces on top of it, all of which could/should have different colours than the plane being solved.
If considering the pentagonal regions as faces, like in the great dodecahedron represented by Schläfli symbol {5,5/2}, then the requirement is for all faces to be monochrome (same color) and for opposite faces to share the same color.
The puzzle does not turn smoothly, due to its unique design. [1]
There are 30 edges, each of which can be flipped into two positions, giving a theoretical maximum of 30!×230 permutations. This value is not reached for the following reasons:
This gives a total of possible combinations.
The precise figure is 72 431 714 252 715 638 411 621 302 272 000 000 (roughly 72.4 decillion on the short scale or 72.4 quintilliard on the long scale).
The Rubik's Cube is a 3-D combination puzzle originally invented in 1974 by Hungarian sculptor and professor of architecture Ernő Rubik. Originally called the Magic Cube, the puzzle was licensed by Rubik to be sold by Pentangle Puzzles in the UK in 1978, and then by Ideal Toy Corp in 1980 via businessman Tibor Laczi and Seven Towns founder Tom Kremer. The cube was released internationally in 1980 and became one of the most recognized icons in popular culture. It won the 1980 German Game of the Year special award for Best Puzzle. As of January 2009, 350 million cubes had been sold worldwide, making it the world's bestselling puzzle game and bestselling toy. The Rubik's Cube was inducted into the US National Toy Hall of Fame in 2014.
The Rubik's Revenge is a 4×4×4 version of the Rubik's Cube. It was released in 1981. Invented by Péter Sebestény, the cube was nearly called the Sebestény Cube until a somewhat last-minute decision changed the puzzle's name to attract fans of the original Rubik's Cube. Unlike the original puzzle, it has no fixed facets: the centre facets are free to move to different positions.
The Pocket Cube is a 2×2×2 version of the Rubik's Cube. The cube consists of 8 pieces, all corners.
Speedcubing is a competitive sport involving solving a variety of combination puzzles, the most famous being the 3x3x3 puzzle or Rubik's Cube, as quickly as possible. An individual who practices solving twisty puzzles is known as a speedcuber, or a cuber. For most puzzles, solving involves performing a series of moves or sequences that alters a scrambled puzzle into a solved state, in which every face of the puzzle is a single, solid color.
The Professor's Cube is a 5×5×5 version of the original Rubik's Cube. It has qualities in common with both the 3×3×3 Rubik's Cube and the 4×4×4 Rubik's Revenge, and solution strategies for both can be applied.
The Square-1 is a variant of the Rubik's Cube. Its distinguishing feature among the numerous Rubik's Cube variants is that it can change shape as it is twisted, due to the way it is cut, thus adding an extra level of challenge and difficulty. The Super Square One and Square Two puzzles have also been introduced. The Super Square One has two additional layers that can be scrambled and solved independently of the rest of the puzzle, and the Square Two has extra cuts made to the top and bottom layer, making the edge and corner wedges the same size.
The Megaminx or Mégaminx is a dodecahedron-shaped puzzle similar to the Rubik's Cube. It has a total of 50 movable pieces to rearrange, compared to the 20 movable pieces of the Rubik's Cube.
The Skewb Ultimate, originally marketed as the Pyraminx Ball, is a twelve-sided puzzle derivation of the Skewb, produced by German toy-maker Uwe Mèffert. Most versions of this puzzle are sold with six different colors of stickers attached, with opposite sides of the puzzle having the same color; however, some early versions of the puzzle have a full set of 12 colors.
The Pyramorphix, also called Pyramorphinx, is a tetrahedral puzzle similar to the Rubik's Cube. It has a total of 8 movable pieces to rearrange, compared to the 20 of the Rubik's Cube. Although it looks like a trivially simple version of the Pyraminx, it is an edge-turning puzzle with the mechanism identical to that of the Pocket Cube.
The V-Cube 6 is a 6×6×6 version of the original Rubik's Cube. The first mass-produced 6×6×6 was invented by Panagiotis Verdes and is produced by the Greek company Verdes Innovations SA. Other such puzzles have since been introduced by a number of Chinese companies, most of which have mechanisms which improve on the original. Unlike the original puzzle, it has no fixed facets: the center facets are free to move to different positions.
The Impossiball is a rounded icosahedral puzzle similar to the Rubik's Cube. It has a total of 20 movable pieces to rearrange, which is the same as the Rubik's Cube, but all of the Impossiball's pieces are corners, like the Pocket Cube.
The V-Cube 7 is a combination puzzle in the form of a 7×7×7 cube. The first mass-produced 7×7×7 was invented by Panagiotis Verdes and is produced by the Greek company Verdes Innovations SA. Other such puzzles have since been introduced by a number of Chinese companies, some of which have mechanisms which improve on the original. Like the 5×5×5, the V-Cube 7 has both fixed and movable center facets.
The Pyraminx Crystal is a dodecahedral puzzle similar to the Rubik's Cube and the Megaminx. It is manufactured by Uwe Mèffert and has been sold in his puzzle shop since 2008.
The Void Cube is a 3-D mechanical puzzle similar to a Rubik's Cube, with the notable difference being that the center pieces are missing, which causes the puzzle to resemble a level 1 Menger sponge. The core used on the Rubik's Cube is also absent, creating holes straight through the cube on all three axes. Due to the restricted volume of the puzzle it employs an entirely different structural mechanism from a regular Rubik's Cube, though the possible moves are the same. The Void Cube was invented by Katsuhiko Okamoto. Gentosha Education, in Japan, holds the license to manufacture official Void Cubes. These official designs are also sold under the Rubik's brand, owned by Spin Master Ltd., and workalikes are available from a variety of manufacturers. Speed-solving the Void Cube is common in exhibition but is not an official World Cube Association competition event.
The Helicopter Cube is a Rubik's Cube-like puzzle invented by Adam G. Cowan in 2005 and built in 2006. It is also in the shape of a cube. At first glance, the Helicopter Cube may seem like a combination of the 2x2x2 and the Skewb, but it actually cuts differently, and twists around cube edges rather than cube faces. The purpose of the puzzle is to scramble the colors, and then restore them back to their original state of a single color per face.
The Layer by Layer method, also known as the beginners method, is a method of solving the 3x3x3 Rubik's Cube. Many beginners' methods use this approach, and it also forms the basis of the CFOP speedcubing technique.
A Tuttminx is a Rubik's Cube-like twisty puzzle, in the shape of a truncated icosahedron. It was invented by Lee Tutt in 2005. It has a total of 150 movable pieces to rearrange, compared to 20 movable pieces of the Rubik’s Cube.
The Nine-Colour Cube is a cubic twisty puzzle. It was invented in 2005 by Milan Vodicka and mass-produced by Meffert's seven years later. Mechanically, the puzzle is identical to the Rubik's Cube; however, unlike the Rubik's Cube, which only has 6 different colours, the Nine-Colour Cube has 9 colours, with the individual pieces having one colour each.
The V-Cube 8 is an 8×8×8 version of the Rubik's Cube. Unlike the original puzzle, it has no fixed facets: the center facets are free to move to different positions. The design was covered by Panagiotis Verdes' patent from 2007 but Verdes Innovations SA did not produce it for sale until 2014. Other 8×8×8 cubes are produced by various Chinese companies.
The Dino Cube is a cubic twisty puzzle in the style of the Rubik's Cube. It was invented in 1985 by Robert Webb, though it was not mass-produced until ten years later. It has a total of 12 external movable pieces to rearrange, compared to 20 movable pieces on the Rubik's Cube.
| Puzzle inventors |  | ||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Rubik's Cubes | |||||||||||||||
| Cubic variations | |||||||||||||||
| Non-cubic variations |
| ||||||||||||||
| Virtual variations (>3D) | |||||||||||||||
| Derivatives | |||||||||||||||
| Renowned solvers |
| ||||||||||||||
| Solutions |
| ||||||||||||||
| Mathematics | |||||||||||||||
| Official organization | |||||||||||||||
| Related articles | |||||||||||||||
