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Rubik's Cube (commonly misspelled ''rubix'', ''rubick's'' or ''rubics'' cube) is a Sculptor and Professor of Architecture Ernő Rubik . Originally called the "Magic Cube" by its inventor, this puzzle was renamed "Rubik's Cube" by 2005 . A Rubik's Cube has nine square facelets on each side, giving fifty-four facelets in total, and occupies a volume of twenty-seven unit Cube s. Typically, the faces of the cube are covered by nine stickers in six solid colours; there is one colour for each side of the cube. When the puzzle is solved, each face of the cube is a solid colour. The cube celebrated its twenty-fifth anniversary in 2005, when a special edition cube in a presentation box was released, featuring a sticker in the centre of the reflective face (which replaced the white face) with a "Rubik's Cube 1980-2005" logo. The puzzle comes in four widely available versions: the 2×2×2 (" Pocket Cube "), the 3×3×3 standard cube, the 4×4×4 (" Rubik's Revenge "), and the 5×5×5 (" Professor's Cube "). Recently, Greek inventor Panagiotis Verdes patented a method of creating cubes beyond the 5×5×5, up to 11×11×11 level. His designs, which include improved mechanisms for the 3×3×3, 4×4×4, and 5×5×5, are suitable for speed cubing, whereas existing designs for cubes larger than 3×3×3 are prone to breaking.[8 As of June 1st, 2007, these designs are still being tested and are not widely available yet, although videos of actual, working prototypes for the 6×6×6 and 7×7×7 have been released. There is also a variation of the Rubik's Cube called a Sudokube . It's a combination with the popular Paper And Pencil Game Sudoku . HISTORY Conception and development In March 1970, Harry D. Nichols invented a 2x2x2 "Puzzle with Pieces Rotatable in Groups" and filed a U.S. patent application for it. Nichols' cube was held together with magnets. Nichols was granted on April 11, 1972, two years before Rubik invented his improved cube. In April 9, 1970, Frank Roxy invented and applied to patent "Spherical 3x3x3", he finally received his UK patent (1344259) on January 16th 1974, but still before Erno Rubik received his. Rubik invented his "Magic Cube" in 1974 and obtained Hungarian patent HU170062 for the Magic Cube in 1975 but did not take out international patents. The first test batches of the product were produced in late 1977 and released to Budapest toy shops. Magic Cube (later "Rubik's Cube") was held together with interlocking plastic pieces that were less expensive to produce than the magnets in Nichols' design. In September 1979, a deal was signed with Ideal Toys to bring the Magic Cube to the Western World, and the puzzle made its debut at toy fairs in January and February 1980. After its international debut, the progress of the Cube towards the toy shop shelves of the West was briefly halted so that it could be manufactured to Western safety and packaging specifications. A lighter Cube was produced, and Ideal Toys decided to rename it. " The Gordian Knot " and "Inca Gold" were considered, but the company finally decided on "Rubik's Cube", and the first batch was exported from Hungary in May 1980. Taking advantage of an initial shortage of Cubes, many cheap imitations appeared. Nichols assigned his patent to his employer Moleculon Research Corp which sued Ideal Toy Company in 1982. In 1984 Ideal lost the patent infringement suit and appealed. In 1986 the appeals court affirmed the judgment that Rubik's 2x2x2 Pocket Cube infringed Nichols' patent, but overturned the judgment on Rubik's 3x3x3 Cube. Moleculon Research Corporation v. CBS, Inc. Even while Rubik's patent application was being processed, Terutoshi Ishigi, a self-taught engineer and ironworks-owner near Tokyo, filed for a Japanese patent in for a nearly identical mechanism, and was granted patent JP55‒8192 (1976); Ishigi's is generally accepted as an independent reinvention. Rubik applied for another Hungarian patent on October 28, 1980 and applied for other patents. In the United States, Rubik was granted on March 29, 1983 for the Cube. Rubik also invented and patented several other puzzles which were not as popular as Rubik's Cube. Popularity Over one hundred million Rubik's Cubes were sold in the period from 1980 to 1982.http://www.rubiks.com/lvl3/index_lvl3.cfm?lan=eng&lvl1=inform&lvl2=medrel&lvl3=cubfct It won the BATR Toy Of The Year award in 1980 and again in 1981. Ideal Toys published a ''Rubik's Cube Newsletter'' from 1982 to 1983. Many similar puzzles were released shortly after the Rubik's Cube, both from Rubik himself and from other sources, including the Rubik's Revenge , a 4×4×4 version of the Rubik's Cube. There are also 2×2×2 and 5×5×5 Cubes (known as the Pocket Cube and the Professor's Cube , respectively) and puzzles in other shapes, such as the Pyraminx , a Tetrahedron . In May 2005, the Greek inventor Panagiotis Verdes constructed a 6×6×6 Rubik's Cube; on May 23 2006 , Frank Morris, a world champion Rubik's Cube solver, tested this version. He had previously solved the 3×3×3 in 15 seconds, the 4×4×4 in 1 minute and 10 seconds, and the 5×5×5 in 1 minute and 46.1 seconds. The 6×6×6 took him 5 minutes and 37 seconds to solve. Morris himself thanked the inventor for making it and purportedly stated that the bigger the Cube is, the greater the pleasure. In July 2006, Mr. Verdes successfully constructed the 7×7×7 cube; on October 27 2006 , a video of Morris testing the cube was released. He solved this cube in 6 minutes and 29.31 seconds. Videos of these tests can be viewed at http://www.olympicube.com. In 1994, Melinda Green, Don Hatch, and Jay Berkenilt created a model of a 3×3×3×3 model. As of January 2007, it has been solved by only 7 people. {Link without Title} In 1981, Patrick Bossert , a twelve-year-old schoolboy from England , published his own solution in a book called ''You Can Do the Cube'' (ISBN 0-14-031483-0). The book sold over 1.5 million copies worldwide in seventeen editions and became the number one book on '' The Times ''. He didn't reach the New York Times Best Seller List for that year {Link without Title} . At the height of the puzzle's popularity, separate sheets of coloured stickers were sold so that frustrated or impatient Cube owners could restore their puzzle to its original appearance.Tim Walsh: "Timeless Toys: Classic Toys And the Playmakers Who Created Them" p233 ISBN 10: 0-7407-5571-4 The name "Rubik's Cube" is common in many languages except Hebrew , Hungarian and German . In the former language, it is known as the "Hungarian Cube", whilst in the latter, its name is "Magic Cube" (''Bűvös kocka'' in Hungarian and ''Zauberwürfel'' in German). WORKINGS A standard Cube measures approximately 2¼ inches (5.7 cm) on each side. The puzzle consists of the twenty-six unique miniature cubes on the surface. However, the centre cube of each face is merely a single square façade; all are affixed to the core mechanisms. These provide structure for the other pieces to fit into and rotate around. So there are twenty-one pieces: a single core piece consisting of three intersecting axes holding the six centre squares in place but letting them rotate, and twenty smaller plastic pieces which fit into it to form the assembled puzzle. The Cube can be taken apart without much difficulty, typically by turning one side through a 45° angle and prying an "edge cube" away from a "centre cube" until it dislodges (however, prying loose a corner cube is a good way to break off a centre cube - thus ruining the cube). It is a simple process to solve a Cube by taking it apart and reassembling it in a solved state; however, this is not the challenge. There are twelve edge pieces which show two coloured sides each, and eight corner pieces which show three colours. Each piece shows a unique colour combination, but not all combinations are present (for example, there is no edge piece with both red and orange sides, if red and orange are on opposite sides of the solved Cube.). The location of these cubes relative to one another can be altered by twisting an outer third of the Cube 90°, 180° or 270°, but the location of the coloured sides relative to one another in the completed state of the puzzle cannot be altered: it is fixed by the relative positions of the centre squares and the distribution of colour combinations on edge and corner pieces. For most recent Cubes, the colours of the stickers are red opposite orange, yellow opposite white, and green opposite blue. However, cubes with alternative colour arrangements also exist, for example they might have yellow face opposite the green, and the blue face opposite the white (with red and orange opposite faces remaining unchanged). Permutations A normal (3×3×3) Rubik's Cube can have (8! × 38−1) × (12! × 212−1)/2 = 43,252,003,274,489,856,000 different positions ( Permutations ), or about 4.3 × 1019, forty-three Quintillion ( Short Scale ) or forty-three trillion ( Long Scale ), but the puzzle is advertised as having only " Billions " of positions, as the larger numbers could be regarded as incomprehensible to many. Despite the vast number of positions, all Cubes can be solved in twenty-six or fewer moves (see Optimal Solutions For Rubik's Cube ). To put this into perspective, if every permutation of a Rubik's Cube was lined up end to end, it would stretch out approximately 261 Light Years . If they were laid side by side, it would cover the Earth approximately 256 times. In fact, there are (8! × 38) × (12! × 212) = 519,024,039,293,878,272,000 (about 519 Quintillion on the Short Scale ) possible arrangements of the pieces that make up the Cube, but only one in twelve of these are actually reachable. This is because there is no sequence of moves that will swap a single pair or rotate a single corner or edge cube. Thus there are twelve possible sets of reachable configurations, sometimes called "universes" or " Orbits ", into which the Cube can be placed by dismantling and reassembling it. Centre faces The original and still official Rubik's Cube has no orientation markings on the centre faces, and therefore solving it does not require any attention to correctly orienting those faces. If you have a marker pen, you could, for example, mark the central squares of an unshuffled Cube with four coloured marks on each edge, each corresponding to the colour of the adjacent face. Some Cubes have also been produced commercially with markings on all of the squares, such as the Lo Shu Magic Square or Playing Card Suit s. Thus one can scramble and then unscramble the Cube yet have the markings on the centres rotated, and it becomes an additional challenge to "solve" the centres as well. This is known as "supercubing". Putting markings on the Rubik's Cube increases the challenge chiefly because it expands the set of distinguishable possible configurations. When the Cube is unscrambled apart from the orientations of the central squares, there will always be an even number of squares requiring a quarter turn. Thus there are 46/2 = 2,048 possible configurations of the centre squares in the otherwise unscrambled position, increasing the total number of possible cube permutations from 43,252,003,274,489,856,000 (4.3×1019) to 88,580,102,706,155,225,088,000 (8.9×1022). SOLUTIONS Many general solutions for the Rubik's Cube have been discovered independently. The most popular method was developed by David Singmaster and published in the book ''Notes on Rubik's Magic Cube'' in 1980. This solution involves solving the Cube layer by layer, in which one layer, designated the top, is solved first, followed by the middle layer, and then the final and bottom layer. After practice, solving the Cube layer by layer can be done in under one minute. Other general solutions include "corners first" methods or combinations of several other methods. Speedcubing solutions have been developed for solving the Rubik's Cube as quickly as possible. The most common speedcubing solution was developed by Jessica Fridrich . It is a very efficient layer-by-layer method that requires a large number of Algorithm s, especially for orienting and permuting the last layer. The first layer corners and second layer are done simultaneously, with each corner paired up with a second-layer edge piece. Another well-known method was developed by Lars Petrus . In this method, a 2×2×2 section is solved first, followed by a 2x2x3, and then the incorrect edges are solved using a 3 move algorithm, which eliminates the need for a 32 move algorithm later. One of the advantages of this method is that it tends to give solutions in fewer moves. For this reason the method is also popular for fewest move competitions. Solutions typically follow a series of steps, and include a set of algorithms for solving each step. An algorithm, also known as a process or an operator, is a series of twists that accomplishes a particular goal. For instance, one algorithm might switch the locations of three corner pieces, while leaving the rest of the pieces in place. Basic solutions require learning as few as 4 or 5 algorithms but are generally inefficient, needing around 100 twists on average to solve an entire cube. In comparison, Fridrich's advanced solution requires learning 53+ algorithms, but allows the cube to be solved in only 55 moves on average. A different kind of solution developed by Ryan Heise uses no algorithms but rather teaches a set of underlying principles that can be used to solve in fewer than 40 moves. A number of complete solutions can also be found in any of the books listed in the bibliography, and most can be used to solve any Cube in under five minutes. The search for optimal solutions See Also: Optimal solutions for Rubik's Cube The manual solution methods described above are intended to be easy to learn, but much effort has gone into finding even faster solutions to Rubik's Cube. In 1982, David Singmaster and Alexander Frey hypothesized that the number of moves needed to solve Rubik's Cube, given an ideal algorithm, might be in "the low twenties". In 2007, Daniel Kunkle and Gene Cooperman used computer search methods to demonstrate that any 3x3x3 Rubik's Cube configuration can be solved in a maximum of 26 moves. |
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