Play the movie while looking at the small white speck in the center of the ring. At first, the ring is motionless and it's easy to tell that the dots are changing color. When the ring begins to rotate, the dots suddenly appear to stop changing. But in reality they are changing the entire time. Take a look.

Top 10 finalists in the 2011 Contest. The one above took Illusion of the Year honors, nine more finalists are at the link.

Falling Comet: "In 1955 "Rock Around the Clock" went to the top of the charts and turned Bill Haley into the king of rock and roll. Twenty-five years later, he was holed up in a pool house in Harlingen, drunk, lonely, paranoid, and dying. After three decades of silence, his widow and his children tell the story of his years in Texas and his sad final days."

Ready to Erase Whiteboards, IdeaPaint Lands 1,700 Lowe's Stores - Bloomberg: Whiteboard paint for any wall.

What Bitcoin Is, and Why It Matters Can a booming "crypto-currency" really compete with conventional cash?

Recent weeks have been exciting for a relatively new kind of currency speculator. In just three weeks, the total value of a unique new digital currency called Bitcoin has jumped four times, to over $40 million.

Bitcoin is underwritten not by a government, but by a clever cryptographic scheme.

For now, little can be bought with bitcoins, and the new currency is still a long way from competing with the dollar. But this explainer lays out what Bitcoin is, why it matters, and what needs to happen for it to succeed.