New Scientist explains -
The visual trick involves a 3D construction of four slopes that appear to extend downwards away from a common centre (see video). When wooden balls are placed on the slopes, however, they bizarrely roll upwards as if a magnet is pulling them.Kokichi Sugihara and all the other contestants are lucky Obama did not enter the contest. The area of illusion is the only one in which I can honestly say Barack Obama is without peer.
But the "Impossible Motion" illusion, created by Kokichi Sugihara of the Meiji Institute for Advanced Study of Mathematical Sciences in Kawasaki, Japan, is soon dispelled when it's viewed from a different perspective – each slope is actually sloping downwards towards a common centre.
We're fooled because we make the assumption that each supporting column of the object is vertical, and that the longest column in the centre is the highest. But in reality, the columns and slopes are angled to create the illusion.
The life of Indigo Red is full of adventure. Tune in next time for the Further Adventures of Indigo Red.