A Japanese miner climbs onto the stage, his helmet light bobbing and a pickax slung over his shoulder. He swings the pick a few times before kneeling to inspect something unusual and then worries at some loose rubble with his hands. Suddenly his face lights up, and he turns to the audience, his newfound riches held forward in his open hands. “I have discovered a new supermagnet that attracts wood,” he announces. Okaaaay....

A video begins playing overhead, and the audience sees four wood balls rolling uphill in open defiance of the laws of gravity. Pulled by a magnet? Not really. The “miner” is mathematical engineer Kokichi Sugihara of the Meiji Institute for Advanced Study of Mathematical Sciences in Kawasaki, Japan, and his magnetlike slopes illusion is the winner of the 2010 Best Illusion of the Year Contest. The trick is exposed when the video shows Sugihara’s slopes from a different vantage point: the wood balls are actually rolling down, not up. The slopes are cleverly designed to produce the antigravity illusion when seen from a specific point of view.

Sugihara’s invention exemplifies several of the most popular themes in illusions today. It relies not only on a trick of perspective but also on perceptual ambiguity. There is more than one way to perceive the “magnetic” slopes, but our visual system’s expectations make us prefer one interpretation—and illusions are a way to fool the brain into revealing those systems. “We are surrounded by many industrial products that are made with right angles, such as desks, boxes and buildings,” Sugihara explains. When confronted with an image in which multiple interpretations are possible, we choose the version that allows us to see rectangular solids. In Sugihara’s prizewinning illusion, none of the columns that support the ramps are vertical. Yet we interpret them all as perfectly straight.

As with many of the newest illusions, Sugihara’s impossible-motion demonstration is dynamic: to fully appreciate the magic, you need to see the balls moving. Although illusionists continue to produce classical illusions using still photographs or even just a few lines on paper, computer and video technologies have made it possible to create increasingly complex moving-picture illusions. Several of the top 10 illusions of 2010 are animations that cannot be shown here, but you can see them in action at http://illusionoftheyear.com.

Because illusions enable us to see things that do not match physical reality, they are critically important to understanding the neural mechanisms of perception and cognition. The annual Best Illusion of the Year Contest celebrates the inventiveness of illusion creators around the world: researchers, software engineers, mathematicians, magicians, graphic designers, sculptors and painters fascinated with mapping the boundaries of human perception.

Whereas scientists once created illusions from simple lines and shapes and artists focused on making eye-popping illusions, the overlap between science and art is now greater than ever. Scientists are using graphic-design tools to make their illusions more artistic, and artists have grown more knowledgeable about the neuroscience behind the magic.

Illusions competing in the contest must be novel—that is, previously unpublished or published no earlier than the year preceding the contest. An international panel of experts selects the 10 illusions that are the most counterintuitive, spectacular, beautiful and significant to the understanding of the human mind and brain. The creators are invited to present their awe-inspiring brain twisters at an awards gala where the audience votes to choose the first-, second- and third-place winners: the “Oscars” of illusion.

Anyone can submit an illusion to the contest, which is sponsored by Scientific American. Instructions are posted at http://illusionoftheyear.com/submission-instructions. The 2011 event is scheduled for Monday, May 9, at the Philharmonic Center for the Arts in Naples, Fla. Please join us and vote for the best illusion of the year!