Visual worlds 2/Chequered sculpture

You move.
The impression of this sculpture is entirely dependent on the position from which you are viewing it. From one position you may perceive the sculpture as a black-and-white chequered surface. (The exact position depends on how tall you are.)
As you move, you see another shape. The sculpture cancels what is called formal constancy, that is, the fact that the world normally appears stable even if we move around in it. Our capacity to perceive the world as constant and stable is truly fantastic and unparalleled. Creating a constant picture of the world puts many demands on the visual system, and this becomes especially clear when we try to construct a constant vision in technical systems, e.g. robots.