|Ambiguous figures have long fascinated artists, children, and others who enjoy surprises. But ambiguity is not only the province of the artist or the enjoyer of novelty. It is present and has significance throughout all of life.
All inputs to the brain, whether man-made or natural, are, to one degree or another ambiguous  in the sense of allowing for multiple interpretations. All input is ambiguous and what we see is always only one of many possible constructions that can be made from that input.
On this page are several illustrations where the ambiguity of input is particularly striking, including both images by artists and photographs. Click on the images to see larger versions, and practice noticing that input always has multiple interpretations.
The two bottom images link to animations. An animation associated with the cube in the lower left may help give you a more direct feeling for the brain actively switching between alternative interpretations. An animation associated with the construction sign illustrates that ambiguous figures have more than two interpretations, and links to an interactive exhibit you can use to further develop your skill at seeing multiple different interpretations.
Additional examples of ambiguous figures elsewhere on the web are linked below.