To construct the deceptive contraption he would enter in an international illusion contest, Kokichi Sugihara contravened a deeply held intuition: gravity works. Sugihara, a mathematical engineer at Meiji University in Japan, built a set of four ramps, arranged in a cross, on which wooden balls appear to roll uphill, as if pulled by a magnet toward the center.

We won't give away the secret (revealed in the video below), but suffice it to say that Sugihara's illusion was clever enough to win the 2010 Best Illusion of the Year contest, held May 10 at the Philharmonic Center for the Arts in Naples, Fla. (Scientific American co-sponsored the event.) The contest, now in its sixth year, is an offshoot of the annual meeting of the Vision Sciences Society, which was being held at a nearby hotel.

A panel of judges whittled the submissions, all of which had to be new or at least unpublished before 2009, to 10 finalists; attendees of the contest gala then voted to determine the best illusions of that group. Rounding out the top three were entries by vision scientist Bart Anderson of the University of Sydney and physiologist Jan Kremlacek of Charles University in Prague.

For more trickery, see our recent slide show of visual illusions.