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corner top left Hypnoptical Illusions  
by Gianni A. Sarcone and Marie J. Waeber

"What if everything is an illusion and nothing exists? In that case, I definitely overpaid for my carpet." 
- Woody Allen

Apparent Movements

The diagram below is static. However, when you stare
(not too close!) at it, at a given time the 3 colored
concentric rings seem to glow and to rotate around
the central sphere

rotating rings

small square Moving flows

Rotating Hearts

With a little concentration, make the hearts around the King
spin in the opposite direction! Yes, it is possible...

king of heart

Disappearing/Appearing Cheshire Cat

Focus your attention on the blue point
to make the Cheshire cat vanish!

cheshire cat

Vanishing black dot(s)

Try now to focus on the blinking dot at the center of the moving pattern below, while doing this the 3 dark dots may disappear and reappear spontaneously (singly, in pairs or all three). Steady vision induce disappearance, gaze shifts induce reappearance!
The animated drawing below is based on an article of the researcher Yoram Bonneh published in Nature (Motion-induced blindness)


Concentric Sets

Stare at the center of the diagram below. Keeping your gaze
fixed on the center, move your head backwards and
forwards. You may see the orange rings rotate counterwise!


small square Pinna Rotor Illusion
small square Anomalous Motion Illusion

Subliminal image

Switch the light in your room and step back about 1 meter from
your computer screen. Then, look at the light points shown below
out of the corner of your eyes (no direct vision!). You may perceive
a furtive figure... If nothing happens, download the image and modify
the light animation speed (approx. 1600 Hertz) until you'll see a... heart!

heart lights
© G. Sarcone

Size of the Moon

Psychologically, we tend to see circular objects larger (or smaller)
than they are in reality. Could you say what is the apparent size
of the Moon? Is it as large as 1, 0.05 or 0.01 euro?
You might be surprised to learn that in fact the moon is
as large as 1 cent of euro (or a US dime) seen at a distance
of about 2 meters! You can verify it...


small square Moon Illusion

Happy / Unhappy ?

The girls in the picture below seems to smile, but if you enlarge the image... This illusion is a kind of ambiguous bistable figure and is produced by merging 2 pixel matrixes having different resolutions. When you see the image closer, the ‘fine’ pixels will dominate (unhappy girl), but when you observe the image from a distance, you can see only the ‘large’ pixels (happy girl). This illusion is based on the optic artwork of Salvador Dali: "Gala Contemplating the Mediterranean Sea Which at Twenty Meters Becomes the Portrait of Abraham Lincoln", 1976.
Enlarge / Reduce image

happy unhappy


© 2005 G. Sarcone,
You can re-use content from Archimedes’ Lab on the ONLY condition that you provide credit to the authors (© G. Sarcone and/or M.-J. Waeber) and a link back to our site. You CANNOT reproduce the content of this page for commercial purposes.

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