22 jun. 2011

Cube Rubik

In March 1970, Larry Nichols invented a 2×2×2 "Puzzle with Pieces Rotatable in Groups" and filed a Canadian patent application for it. Nichols's cube was held together with magnets. Nichols was granted U.S. 

Patent 3,655,201 on April 11, 1972, two years before Rubik invented his Cube. On April 9, 1970, Frank Fox applied to patent his "Spherical 3×3×3". He received his UK patent (1344259) on January 16, 1974.
In the mid-1970s, Ernő Rubik worked at the Department of Interior Design at the Academy of Applied Arts and Crafts in Budapest. Although it is widely reported that the Cube was built as a teaching tool to help his students understand 3D objects, his actual purpose was solving the structural problem of moving the parts independently without the entire mechanism falling apart. He did not realize that he had created a puzzle until the first time he scrambled his new Cube and then tried to restore it.
Rubik obtained Hungarian patent HU170062 for his "Magic Cube" in 1975. Rubik's Cube was first called the Magic Cube (Buvuos Kocka) in Hungary. The puzzle had not been patented internationally within a year of the original patent. Patent law then prevented the possibility of an international patent. Ideal wanted at least a recognizable name to copyright; of course, that arrangement put Rubik in the spotlight because the Magic Cube was renamed after its inventor.
The first test batches of the product were produced in late 1977 and released to Budapest toy shops. Magic Cube was held together with interlocking plastic pieces that prevented the puzzle being easily pulled apart, unlike the magnets in Nichols's design. In September 1979, a deal was signed with Ideal to bring the Magic Cube to the Western world, and the puzzle made its international debut at the toy fairs of London, Paris, Nuremberg and New York in January and February 1980.
Nichols assigned his patent to his employer Moleculon Research Corp., which sued Ideal in 1982. In 1984, Ideal lost the patent infringement suit and appealed. In 1986, the appeals court affirmed the judgment that Rubik's 2×2×2 Pocket Cube infringed Nichols's patent, but overturned the judgment on Rubik's 3×3×3 Cube.

Greek inventor Panagiotis Verdes patented a method of creating cubes beyond the 5×5×5, up to 11×11×11, in 2003 although he claims he originally thought of the idea around 1985. As of June 19, 2008, the 5x5x5, 6x6x6, and 7x7x7 models are in production in his "V-Cube" line. 
The Cube has inspired an entire category of similar puzzles, commonly referred to as twisty puzzles, which includes the cubes of different sizes mentioned above as well as various other geometric shapes. Some such shapes include the tetrahedron (Pyraminx), the octahedron (Skewb Diamond), the dodecahedron (Megaminx), the icosahedron (Dogic). There are also puzzles that change shape such as Rubik's Snake and the Square One.
In Rubik's cubists' parlance, a memorised sequence of moves that has a desired effect on the cube is called an algorithm. This terminology is derived from the mathematical use of algorithm, meaning a list of well-defined instructions for performing a task from a given initial state, through well-defined successive states, to a desired end-state. Each method of solving the Rubik's Cube employs its own set of algorithms, together with descriptions of what the effect of the algorithm is, and when it can be used to bring the cube closer to being solved.
Most algorithms are designed to transform only a small part of the cube without scrambling other parts that have already been solved, so that they can be applied repeatedly to different parts of the cube until the whole is solved. 
Some algorithms have a certain desired effect on the cube but may also have the side-effect of changing other parts of the cube. Such algorithms are often simpler than the ones without side-effects, and are employed early on in the solution when most of the puzzle has not yet been solved and the side-effects are not important. Towards the end of the solution, the more specific (and usually more complicated) algorithms are used instead, to prevent scrambling parts of the puzzle that have already been solved.
The most popular method was developed by David Singmaster and published in the book Notes on Rubik's "Magic Cube" in 1981. David's solution consisted to use a notation developed by him to denote a sequence of moves, referred to as "Singmaster notation". Its relative nature allows algorithms to be written in such a way that they can be applied regardless of which side is designated the top or how the colours are organised on a particular cube. After practice, solving the Cube layer by layer can be done in under one minute.
In 2007, Daniel Kunkle and Gene Cooperman used computer search methods to demonstrate that any 3×3×3 Rubik's Cube configuration can be solved in 26 moves or fewer.In 2008, Tomas Rokicki lowered that number to 22 moves,and in July 2010, a team of researchers including Rokicki, working with Google, proved the so-called "God's number" to be 20. This is optimal, since there exist some starting positions which require at least 20 moves to solve.
A solution commonly used by speed cubers was developed by Jessica Fridrich. It is similar to the layer-by-layer method but employs the use of a large number of algorithms, especially for orienting and permuting the last layer. Fridrich's solution requires learning roughly 120 algorithms but allows the Cube to be solved in only 55 moves on average.

Although there are a significant number of possible permutations for the Rubik's Cube, there have been a number of solutions developed which allow for the cube to be solved in well under 100 moves.
In 1997, Denny Dedmore published a solution described using diagrammatic icons representing the moves to be made, instead of the usual notation.

Speedcubing (or speedsolving) is the practice of trying to solve a Rubik's Cube in the shortest time possible. There are a number of speedcubing competitions that take place around the world.
The first world championship organised by the Guinness Book of World Records was held in Munich on March 13, 1981. All Cubes were moved 40 times and lubricated with petroleum jelly. The official winner, with a record of 38 seconds, was Jury Froeschl, born in Munich. The first international world championship was held in Budapest on June 5, 1982, and was won by Minh Thai, a Vietnamese student from Los Angeles, with a time of 22.95 seconds.
Since 2003, the winner of a competition is determined by taking the average time of the middle three of five attempts. However, the single best time of all tries is also recorded. The World Cube Association maintains a history of world records.
The World Cube Association only sanctions blindfolded, one-handed, and feet solving as official competition events.
The current world record for single time on a 3×3×3 Rubik's Cube was set by Feliks Zemdegs, who had a best time of 6.24 seconds at the Kubaroo Open 2011. The world record for average time per solve is also currently held by Feliks, who set 7.87 seconds at the Melbourne Summer Open 2011.
On March 17, 2010, 134 school boys from Dr Challoner's Grammar School, Amersham, England broke the previous  Guinness World Record for most people solving a Rubik's cube at once in 12 minutes. 

5 comentarios:

  1. Me gustaría intentar el de 9x9x9 jaja, aunque vamos, para mi el de 3x3x3 es un reto más que suficiente xD
    Tuve una época de intentar aprenderme los algoritmos que hay por ahí en internet y aún conseguí hacer alguno, pero ahora no puedo ni con el de 2x2x2 que me compré de recuerdo en Londres jaja.
    Buena entrada =)

  2. jaja, yo hubo un tiempo en el que también miré como resolver el cubo Rubik mediante algoritmos pero vamos, como tú, sólo el de 3x3x3, los del 4x4x4 en adelante buf, demasiado difíciles me parecen.

  3. Pero al final conseguiste resolver el que te compraste conmigo? Porque la última cara se te resistia xD

  4. aiba, casi casi, me quedan dos cuadrados y ya, pero buf, si lo intento se me deshace alguna parte así que está casi acabado pero bueeeeeno, habrá que mirar algún algoritmo porque sino...........=S

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