The image was a sketch of a rabbits head, or was it a ducks head?
Both images seemed to switch back and forth from being a duck then being a rabbit.
The duck-rabbit illusion is a classic one, but its certainly not the first.
The prehistoric artworks found in the cave of Font-de-Gaume, in France, is especially noteworthy.
In this piece, both the mammoth and the bison are shown sharing the same contour.
This carving from a spear-thrower features one image that can be seen two different ways.
Images courtesy of Duncan Caldwell
Andrew Howley writes inNational Geographic:
The details in question are the eyes.
This illusion is unambiguous.
This bas-relief clearly shows two animals sharing a single head.
Depending on which creature you focus, you should see an elephant or a bull.
