Ehrenstein Contour Illusion

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lines per side
thickness
length
The area between radial lines appears brighter than the background. This apparent discrepancy in brightness produces the illusion of circles or squares in between the radial lines. This contour illusion was found by the German psychologist Walter Ehrenstein in 1941.

External Links

Illusory Contour Figures (Wolfram MathWorld)

Permanent Citation

Michael Schreiber
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​"Ehrenstein Contour Illusion"​
​http://demonstrations.wolfram.com/EhrensteinContourIllusion/​
​Wolfram Demonstrations Project​
​Published: September 28, 2007