This ambiguous video of the author's bust
demonstrates an interpretive essence of human vision.
The objects we perceive are just an interpretations based
on the structure of images...
Spinning Lady
Does the spinning lady appear to be circling in a clockwise or counter-clockwise motion to you?
Try to concentrate a bit to change the course of motion.
Human visual system has to build up a 3D representation out of 2D data, but in many cases
this process is ambiguous.