:: Eric Shamblen’s Puzzle Blog ::

What is God’s Number?  It’s a phrase coined in 1982 to describe the minimum number of moves to solve any disordered Rubik’s Cube, the puzzle that swept the globe in the early ’80s.  The smallest number that had previously been proven was 27, but two researchers at Boston’s Northeastern University, graduate student Dan Kunkle and Professor Gene Cooperman, have used supercomputers to show that 26 is the new minimum - and they hope to push that number 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,” said Kunkle in an interview with the London Daily Telegraph.  Theoretical research indicates God’s Number will turn out to be in the low twenties, but proving it is another matter.

 There are 43 billion billion possible Rubik’s cube positions; using brute force, the problem would take far too long to solve even for a supercomputer that can analyze 100 million configurations per second.  Kunkle and Cooperman’s approach was to break the puzzle down into two steps.  Rather than ask the computer to fully solve the puzzle, they programmed it simply to find one of 15,000 known partial solutions, each of which would then only require a few moves to finish.   Using this method, most random cube configurations could be shown to be solvable in 26 moves or less, but a few special configurations still required as many as 29.   The researchers then focused on that problematic minority, and one by one were able to prove that each one of them could actually be solved in less than 26 moves.

The findings were announced at the International Symposium on Symbolic and Algebraic Computation in Ontario, Canada.

A contest was held recently in Zanesville, Ohio, to determine what artwork would be made into the Eastside Community Ministry’s 2007 jigsaw puzzle. Sponsored by the Zanesville Appalachian Arts Project, this annual contest provides local artists with an unusual opportunity to have their artwork made into a cerebral challenge. It also serves as a fundraiser for the Ministry, with proceeds going to its programs designed to “break the cycle of poverty” in the rural community.

This year’s winner was Debby Johnston, who beat out eight other entrants with her watercolor “The Zanesville Farmer’s Market.” She was the runner-up last year, losing to Mary Ann Bucci who painted the “Y-Bridge,” a local historic landmark.

Sales of the puzzle go to help local after-school and summer programs, including 4-H, Bible Club, and the Girl Scouts and Boy Scouts.

Researchers in a study published in 2006  in Psychological Medicine from the University of New South Wales in Sydney, Australia, found that individuals with high “brain reserve” - a combined measure of an individual’s education, occupational complexity, and mentally stimulating pursuits - have a 46% smaller risk of dementia than those with low brain reserve.

In 2003, a study reported in the New England Journal of Medicine found that people who participated in activities such as board games, reading, playing a musical instrument or working a crossword puzzle were less likely to develop dementia than those who engaged in those types of activities rarely or not at all.

Dr. Ronald Petersen, director of the Mayo Clinic Alzheimer’s Disease Research Center, said many different mental activities may help ward off the effects of aging. “Whether it’s a computer game, crossword or Sudoku puzzles, or reading and analyzing a newspaper or magazine, first and foremost seniors should like what they’re doing,” Petersen said. “If the senior does not enjoy the activity, then it is not as likely to be beneficial.”