US Edition If you have been struggling with that Rubik's Cube since the toy's launch more than two decades ago, look away now.
Any configuration of a Rubik's Cube can be solved in 26 moves, or less, according to Dan Kunkle and Prof Gene Cooperman at Northeastern University, Boston.
Historically the best that had been proved was 27 moves. But the pair believe that with more work they could push the count even lower.
"We don't yet have a proof that 25 moves suffice, but we have several new directions to try that we hope will get us there before the end of the year," Mr Kunkle told The Daily Telegraph yesterday.
The ultimate solution to the Rubik's cube has come closer thanks to hours of number crunching conducted on a supercomputer, which took 63 hours to crank out the proof.
They used a brute force method of trying various combinations in the computer, relying on an extra 7000 gigabytes of storage. But the solution was cleverer than trying all possible because cranking through the 43 billion billion possible Rubik's cube positions would take too long even for a supercomputer that can study 100 million configurations per second.
Instead, the scientists used a two-step technique in their calculations. Initially, they programmed the supercomputer to arrive at one of 15,000 half-solved solutions that they knew could be fully solved with a few extra moves.
This suggested that any disordered cube could be fully solved in a maximum of 29 moves, but that most cubes took 26 moves or fewer. The researchers then focused on the small number of "problem" configurations that required more than 26 moves, using the supercomputer to search for the best way to fully solve them. As it turned out the supercomputer was able to fully solve all of these problem cases in fewer than 26 moves.
The study brings scientists one step closer to finding "God's Number" which is the minimum number of moves needed to solve any disordered Rubik's cube. It was so named by two researchers in 1982 because God would only need the smallest number of moves to solve a cube. Theoretical work suggests that God's Number is in the "low 20s".
Mr Kunkle and Prof Cooperman announced their findings at the International Symposium on Symbolic and Algebraic Computation in Waterloo, Ontario.
Dr Simon Singh, maths populariser and author of bestselling book Fermat's Last Theorem, commented yesterday: "These sort of problems seem pointless, but the techniques required to tackle them are fantastically clever and point the way to solving a whole range of so-called combinatorial problems, which have real world applications."
"Although this problem required supercomputers, it is important to remember that obtaining the solution relied on a series of clever shortcut algorithms developed by human mathematicians. This is a triumph for the human carbon brain, not just the computer silicon chip."
Rubik's Cube, invented in the 1970s by Erno Rubik of Hungary, was launched in earnest by Ideal Toys in 1980.