Rendered Escher
Robert van der Steeg (robbie73)
Author's comment - "I found the tower of Escher somewhere in the Somali dunes.".
See also computer images with impossible figures by Robert van der Steeg.
Author's Flickr photostream http://www.flickr.com/photos/robbie73/
The image was found at http://www.flickr.com/photos/robbie73/2644689893/