The Rubik's Cube is
a 3-D mechanical puzzle invented in 1974 by Hungarian sculptor and
professor of architecture Erno Rubik. Originally called the "Magic
Cube", the puzzle was licensed by Rubik to be sold by Ideal Toys in
1980 and won the German Game of the Year special award for Best
Puzzle that year. As of January 2009, 350 million cubes have sold
worldwide making it the world's top-selling puzzle game. It is
widely considered to be the world's best-selling
toy.
In a classic Rubik's
Cube, each of the six faces is covered by nine stickers, among six
solid colours (traditionally white, red, blue, orange, green, and
yellow). A pivot mechanism enables each face to turn independently,
thus mixing up the colours. For the puzzle to be solved, each face
must be a solid colour. Similar puzzles have now been produced with
various numbers of stickers, not all of them by Rubik. The original
3×3×3 version celebrates its thirtieth anniversary in
2010.
Mathematics.
The original (3×3×3) Rubik's Cube has eight corners and twelve
edges. There are 8! (40,320) ways to arrange the corner cubes.
Seven can be oriented independently, and the orientation of the
eighth depends on the preceding seven, giving 3^7 (2,187)
possibilities. There are 12!/2 (239,500,800) ways to arrange the
edges, since an odd permutation of the corners implies an odd
permutation of the edges as well. Eleven edges can be flipped
independently, with the flip of the twelfth depending on the
preceding ones, giving 211 (2,048) possibilities.
There are exactly 43,252,003,274,489,856,000 permutations, which is
approximately forty-three quintillion. The puzzle is often
advertised as having only "billions" of positions, as the larger
numbers could be regarded as incomprehensible to many. To put this
into perspective, if every permutation of a 57-millimeter Rubik's
Cube were lined up end to end, it would stretch out approximately
261 light years!!!!
WOW!!
