Variations.

# Variations.

### Variations of the Rubik's Cube.

There are many variations of the Rubik's Cube. For instance, there is a 'smaller' 2x2x2 cube (named: Pocket Cube) consisting of only eight cubies. But there also exists 'bigger' cubes like a 4x4x4 cube (Rubik's Revenge) and a 5x5x5 cube (Professor's Cube). Only after many years, engineerers have also devised a 6x6x6 cube (V-Cube 6) and a 7x7x7 cube (V-Cube 7). The number of possible positions for these larger cubes explodes exponentially with the size of the cube. Also, the interior of the 6x6x6 and 7x7x7 cubes is very complex, and they both contain entirely hidden movable pieces inside the cube. Without these non-colored pieces, they cube would either fall apart when in use, or certain moves would be impossible to make because of collisions inside the cube. Although it is not much more difficult to determine the amount of possible positions for cubes larger than the original cube, there is not much known about the Diameter of the Cayley Graph of any of the cubes larger than 3x3x3. Apart from these logical extentions in size, there exists some exotic shaped variations, like cubes in the size of the other four polyhedron; and the Square One Variation.

### Speedcubing.

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. In 2004, the WCA made it mandatory to use a special timing device called a Stackmat timer. In addition to official competitions, informal alternative competitions have been held which invite participants to solve the Cube in unusual situations. Some such situations include:

* Blindfolded solving

* Solving the Cube with one person blindfolded and the other person saying what moves to do, known as "Team Blindfold"

* Solving the Cube underwater in a single breath

* Solving the Cube using a single hand

* Solving the Cube with one's feet

Of these informal competitions, the World Cube Association only sanctions blindfolded, one-handed, and feet solving as official competition events. In blindfolded solving, the contestant first studies the scrambled cube (i.e., looking at it normally with no blindfold), and is then blindfolded before beginning to turn the cube's faces. Their recorded time for this event includes both the time spent examining the cube and the time spent manipulating it. 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 6.77 seconds at the Melbourne Cube Day 2010. The world record average solves is currently held by Feliks Zemdegs, which is 7.91 set at the same event. 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. The previous record set in December 2008 in Santa Ana, CA achieved 96 completions.

An example of a very fast speedcuber: Speedcubing (example).

A tutorial of becoming a speedcuber: Speedcubing (tutorial).

An example of a one-handed speedsolver: One-handed speedsolver.

Here is a robot solving a cube (very nice): Computer Rubik's Solver.

And here's someone who solves two cubes at the same time and thus using only one hand per cube: Two solves at the same time.