My Interesting Files

The video is not a computer graphic, but a real scene. In this video, the behavior of the balls seems impossible, because it is against the gravity. And what actually happening is that the orientations of the slopes are perceived oppositely, and hence the descending motion is misinterpreted as ascending motion. This illusion is remarkable in that it is generated by a three-dimensional solid object and physical motion, instead of a two-dimensional picture.
This illusion had won the Winner of the Best Visual Illusion of the Year Contest 2010.

via : Illusion of the Year