Artifact #2
Note: There are two versions of this image. The first is a normal,
full-color image. The second is for stereoscopic viewing with
red-blue 3D glasses. A couple of pairs of glasses are available
in Grail. Sit directly in front of the monitor and relax your eyes...
you should be able to see a single 3D image.
Escher's Study
Escher's Study (Stereoscopic version)