That looks like somebody looking at you crosseyed.

Now, look back at him crosseyed.  Cross your eyes far enough that you fuse the image from the right eye with the image from the left eye.

Now, you see three Cyclops, that trio of one-eyed gods of ancient times.  The one in the middle is seen stereoscopically:  His eye is in front, and his pupil is now seen to actually be a retina, located far in the back of his head.

Study of stereopsis, and discovery of stereopsis blindness, was the major work of one-time radar engineer, Bela Julesz of Bell Telephone Laboratories (now Lucent Technologies).  His study of seeing through snow on radar screens led to his development of the random-dot stereogram as a research tool.  He named his field of study, "Cyclopean perception" because it deals with brain activity in the visual cortex, located in the back of the brain where information from the two eyes is combined and processed.  Julesz called this "the cyclopean retina."

Stereopsis is a fascinating phenomenon to study, to play with, to develop into extensions of our perception.  It's also a valuable exemplar for helping us understand and form useful models for other human information processing skills.

some links	Stereopsis is a feature of many pages on this web site.  Many pages have stereoscopic backgrounds.  Many stereoscopic pairs of photo are used on a variety of pages in a variety of ways.  Some of the clues to puzzles are presented stereoscopically.  Page Backgrounds
	Bumpy mattress surface under street map "The world is three dimensional."
	Starry, starry night -- in 3-D Visual errors
	Starry, starry night -- in 3-D Gateway into Knowledge for Use from Explore Portland!
	Starry, starry night -- in 3-D Secrets of Life -- from above gateway
	Starry, starry night -- in 3-D Navigating Explore PDX and Knowledge for Use  --  in Explore! Portland
	Purple-prosed curses A particularly difficult problem -- on the web as elsewhere
	K U P  floating in 3-D like settling sediment Truth -- Rational or Irrational?
	K U P  floating in 3-D like settling sediment Truth -- Science or Non-science?
	K U P  floating in 3-D like settling sediment Original first page of site
	A rotating K N O The Knowledge for Use Logo
	Purple-prosed curses  (background in table)  --  in Explore! Portland "When neither side can see the viewpoint of the other side..."
	Purple-prosed curses  (background graphic in table)  --  in Explore! Portland Social wellness -- Healthy and unhealthy relationships
	Magic  (background graphic in table)  --  in Explore! Portland Beyond the edges of human comprehension
	Stereo Pair Photos
	Stereo pair from Rainbow Bridge Photogrammetry
	Posters illustrating visual phenomena  Da Vinci Days, July, 2000
	Southwest Community Center The stereoscopic model
	Denver, Colorado -- in 1948 The stereoscopic model
	Roses  --  in Explore! Portland "What Gold Medal rose is located in all three of our rose gardens?"
	The Giant Bird's Eye View  --  in Explore! Portland Consider extending your perceptions with a little know-how.
	Mogen David — with a magical twist.  --  in Explore! Portland Stereoscopic sculpture
	Mogen David — with multiple magic.  --  in Explore! Portland Multiple stereoscopic sculpture
	Trilliums — with multiple mistakes.  --  in Explore! Portland Some botanical sports — at Tryon Creek State Park Trillium Festival, 2002
	Large stereo pairs —   in Explore! Portland Trillium — Old Maid's Bloomers — Silicon
	Duplicate of above, but smaller —   in Explore! Portland Smaller because eye divergence is used.
	Mind-Dancing Into Magic  --  in Explore! Portland Discovering how to see like a giant: extend your 3-D vision.
	Trail construction -- two sets of photos  --  in Explore! Portland Discovering how to see like a giant: extend your 3-D vision.
	Trail construction -- stairs with railing  --  in Explore! Portland Discovering how to see like a giant: extend your 3-D vision.
	Land of impossible streets -- as seen by a giant  --  in Explore! Portland Discovering how to see like a huge giant (helicopter vision).
	Single-photo Stereoscopic Photos
	Hardware cloth Da Vinci Days, July, 2000
	Crystal model Ball-and-stick model: simple cubic lattice  --  in Explore! Portland
	Typewriter Stereograms
	"Stereopsis is simply one out of many..." Seeing Science -- Mysteries at the edge...
	Quantum leaps are for the birds... This is probably how you got here.
	This isn't really from a typewriter... But it could have been.
	Random Dot Stereograms
	The Knowledge for Use Logo
	The first random-dot integrated-image stereogram   —   in Explore! Portland
	Wallpaper that startles Da Vinci Days, July, 2000
	Phantograms
	Amazing stereoscopic images
	The clue that reveals The Platinum Plover Egg is stereoscopic

  A Web site with a strong stereoscopic flavor: Donald Simanek, (physicist)