Take a look at this
Then have a look at this
What do you see?
If you see what I see, you see puddles of water in the impressions in the rock in the first photo, then in the second photo it looks like the water is standing up out of the rock, almost like those scattered drops of mercury that would fly across the floor if you dropped an old thermometer.
This is the same photo. First time shown to you the way I took it, and the second time with it rotated through 180 degrees. Isn’t that stunning?
By the way, these are the markings carved into rocks of the Kilmartin valley, in Scotland, in Neolithic times.
Heroes Not Zombies 
I could explain the perceptual psychology that makes that happen, but that might spoil a wonderful photo experience, so I won’t… 🙂 OK, one clue: light sources. Stunning photos and effect!
Hey Benjamin, don’t hold yourself back – I don’t think explanations diminish experiences! Go on, share your knowledge and understanding. I’d appreciate it.
That is so neat! Ya got me! And I should know better, having learned the technique of making things appear lifelike/3D in art class. It’s interesting how many artists have problems painting very dark complexions believably, Rowena Morrill got it right though. She used lighter colors on the image as you would normally use darker colors to get the lifelike look. I’ll see if I can find a link to her works so you can see for yourself, if I do I will comment below, so watch your spam filter.
Ok, on page one of her gallery the black Unicorn in “Unicorn and Pegasus” shows some of the technique she used.
http://www.rowenaart.com/gallery.html
But doing a Yahoo image search for “Rowena Morrill art” brought up the very image I was thinking of, the last image on page five. A dark complected serpentine mermaid, one of my very favorite images by her. I’m also fond of her portrayls of Wizards in their laboratories (and the whimsical assortment of items in the image) and cats.
http://images.search.yahoo.com/search/images?p=Rowena+Morrill+art+&y=Search&ei=UTF-8&js=1&ni=20&fr=yfp-t-471&b=81
Here is the image from the site the image search pulled up. http://www.ice-haven.com/rowena/rm19.jpg
Adding, I know the factoid about Rowena because I once owned a full set of her art collector cards, and that was a blurb written/given by the artist on one.
Ok, artist’s explanation, and I am not sure I’ll explain as well as Benjamin. But my grasp of it is, it has to do with how we percieve depth. The shadows are on the “bottom”. So, reversing the image (Because that put the highlights on the top of the image and caused us to focus on the shadows, and focusing on the shadows made percieve the depth differently.) gave us cognitive dissonance, so our mind leapt to a conclusion to make sense of things. This is why I meandered off about painting dark complexions, because in this case putting the light colors where we’d normally see dark colors is “right” and makes things more lifelike.
Also, the light source is obviously away from the camera, yet the shadows are nearest to the camera on the bottom image. So, it tricks the mind into percieving it as shading on a convex surface, not a concave one.