Kinetic Illusions

Kinetic Illusions 1

by Gianni A. Sarcone and Marie-Jo Waeber

"Credo ut intelligam,
non intelligo ut credam"

Saint Anselm

• Subjective shade
• Linear vs rotational
• Trapezoid window
• Next page (more...)

Subjective Movements

This spiral seems to spin, it just vibrates but does not rotate	You may see 3 different discs rotate, actually one only does it

Although the disc rotates clockwise, the spirals seem to spin in opposite directions!	The rotational motion of the disc makes the "rays" of the geometrical shape flutter irregularly

Which direction is the rotation? Some spokes appear to rotate CW while the disc rotates CCW	The rotation creates a 3D depth effect. To enhance the effect stare at the center of the disc

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Quick links

Subjective Shades ¬ top

Stare at this disc, the corners of the spinning square create dark zones	If you look at this disc for a while, you may see colors (green and purple pastel shades)

Make Your Own Magic Spinning Top!

Optical linear motion converted
into rotational motion ¬ top

The circular patterns A and B below may spin if you slide a grid (a transparent overlay pattern representing vertical stripes) across them!

Pattern A
pattern A

Vertical stripes
stripes

Example in motion
disc spinning

Pattern B (variant of A)
pattern B

Vertical stripes
stripes B

Example in motion
example in motion

Another curious example of optical motion
with static images
The image below represents a printed card with a curious design consisting of a collection of vertical lines. These lines contain information about six different images, that together form an animation ('Dancing Man'). As a green grid is slid to and fro, different selections of lines become visible, and the animation appears!

kinetic card
These cards, called Kineticards, have different designs
(currently these are only available from the artist)
Eye Think, Inc.
971 Commonwealth Ave.
Boston, MA 02215

Related book:

Magic Moving Images
by Colin Ord
Intriguing optically animated artworks!

Trapezoid window illusion ¬ top

The trapezoid window illusion shows that our perceptions do not always give us correct information about the physical stimulus. When the trapezoid window is in continuous rotation and it is observed with one eye only, it seems to move back and forth like a pendulum (while in reality it is spinning round and round!). This occurs because the brain is interpreting the longer side of the trapezoid as being closer, and the shorter side as being farther away, even when they are not! (When the longer side is really farther away, we mistakenly see it as closer, just like the closer side of a moving rectangle)
trapezoid window

Continue to page 2

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Kinetic illusion page 1 ¬ top
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