Illusory Contour Figures


Radial line segments whose inward-pointing end produce the illusion of a circle or other figure. The apparent figure has the same color as the background, but appears brighter. A similar effect is obtained in the Kanizsa triangle.


The contour illusion above is sometimes known as the Ehrenstein illusion.

See also

Ehrenstein Illusion, Kanizsa Triangle

This entry contributed by Margherita Barile

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McCourt, M. "Ehrenstein Illusion." Eye Research Institute. "Circles That Aren't There."

Referenced on Wolfram|Alpha

Illusory Contour Figures

Cite this as:

Barile, Margherita. "Illusory Contour Figures." From MathWorld--A Wolfram Web Resource, created by Eric W. Weisstein.

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