Shapes such as segments or angles appear larger when placed inside a larger angle.
Angle Illusions
See also
Ponzo's IllusionThis entry contributed by Margherita Barile
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References
Carraher, R. G. and Thurston, J. B. Optical Illusions and the Visual Arts. New York: Reinhold, 1966.Referenced on Wolfram|Alpha
Angle IllusionsCite this as:
Barile, Margherita. "Angle Illusions." From MathWorld--A Wolfram Web Resource, created by Eric W. Weisstein. https://mathworld.wolfram.com/AngleIllusions.html