MUTilated stable posiTIONS

At transitions, brief, unstable composites of the two images may be seen; these are often organized.

clear, high-contrast images disappear and reappear at random. It interests people who see it as a key to the ancient problem of singleness of vision: why, when we have two eyes each of which can support perception by itself, we don't see two of everything. Photographs of craters, from either the moon or other planets including our own, can exhibit this phenomenon.

http://en.wikipedia.org/wiki/Multistable_perception