I've got vision on my brain grapes

A fellow graduate student e-mailed me this awesome picture...I mean...Look at this awesome picture I took back in the early 1900's.

{phew, that was close}

Before I tell you anything about this picture, take a quick look at it.

You probably see a large Jesus-shaped head floating between two people. Yes? Take a second look at the picture, and try to get a different perception of the "hey zeus" patch. This is a bit trickier. What if I told you that you could also see that patch as a child sitting on the left man's knee? Still can't see it? Cover up the floating head's hairdo. Still nothing?! Come on, people! Ok, ok, the floating head's "eye" is actually the child's face cowled under a white hood, and the giant head's mouth is the kid's arm coming out of a white sleeve. Got it? Finally, I was beginning to worry about your brain grapes.

So this is my awesomely ambiguous photo for which I've won numerous Nobel Prizes. What's causing this double perception? Perceptual grouping at its finest, AKA figure-ground, betches!

You may be familiar with the concept of figure-ground from the ambiguous vase/face picture. I've just found a rather unique example of this:

This drawing can be perceived as either one face or two, depending on what you group as the figure and what as the ground. If you perceive the vertical object under the candle as being closer in the picture plane, then you will perceive the eyes, nose, and mouth as belonging to one face that is behind the candlestick. BUT, if you can split your perception to include two faces looking at each other head on, then you will see those faces as being in front and the shape under the candle as being farther (and maybe not even a candlestick anymore, but an accidentally candlestick-shaped space formed by the contours of the two faces). For me, this picture is also bistable, meaning my perception of what's in front switches automatically as I continue looking at the image.

Another famously bistable image is the Necker cube:

From this single simple wire-framed cube, you can get two depth perceptions. The front face can look like it's pointing down and to the left {"Back and to the left. Back and to the left."} or up and to the right. What you "see" will flip back and forth as you continue looking at it. Wh-Wh-What?!?!? Oh my god, it's wonderful!!! {that's for you, Nate}

Awww, perception. My one and only friend. Maybe Perception and I should get together for a round of Boggle this weekend. I sense good times on the horizon, people!


Old-timey photo from some crazy website.
Figure-mutha-truckin-ground from some other such site.