Scientists have cranked through the numbers and determined that no matter how you mangle a Rubik's Cube, if you're doing it right you can theoretically solve the puzzle in 20 moves or fewer. By doing it right, we mean doing it like a supercomputer: Researchers tapped Google's spare computing power to burn through the Cube's 43,252,003,274,489,856,000 starting positions. Even given Google's processing power, the team--which included a mathematician, a Google engineer, a math teacher, and a programmer--could not solve the problem using brute force alone. They had to take all the starting positions and divide them into more manageable chunks, 2.2 billion smaller groups called "corsets," which Google's computers could solve simultaneously.
"The primary breakthrough was figuring out a way to solve so many positions, all at once, at such a fast rate," says Tomas Rokicki, a programmer from Palo Alto, California, who has spent 15 years searching for the ...
