Classic geometrical illusion 20

Classic geometrical illusion 20

since February 13, 2016

Kohara, M. (2006). The role of horizontal components in the tilting letter-row illusion. Ritsumeikan Bungaku Gakusei Ronshu (Student Journal of Ritsumeikan University College of Letters), 12, 83-103.

Kohara-mojiretsu-tilt2006.pdf

Wade, N.J. (2014). Geometrical optical illusionists. Perception, 43, 846-868.

https://journals.sagepub.com/doi/abs/10.1068/p7695

A demo of the Ebbinghaus illusion

The shrimp surrounded by smaller ones in the right group appears to be larger than the shrimp surrounded by larger ones in the left group, though they are the same size.

Ebbinghaus illusion (Titchener illusion)

"Line segment curvature illusion 2"

Each line segment appears to curve inward.

This image includes two types of illusory emoticons.

"Line segment curvature illusion 3"

Each side appears to curve inward.

"A tilt illusion"

Horizontally aligned rows appear to tilt alternately. The uppermost and third rows appear to tilt counterclockwise whereas the rest clockwise.

"Optimized Lipps illusion"

Horizontally aligned rows appear to tilt alternately. The uppermost and third rows appear to tilt counterclockwise whereas the rest clockwise.

"Café Wall illusion with oblique line segments"

Horizontally aligned rows of oblique gray line segments appear to tilt alternately. The uppermost, third and fifth blocks appear to tilt counterclockwise whereas the rest clockwise.

"Wavy Fraser illusion"

Blocks of wavy lines are aligned horizontally, but the uppermost, third and fifth blocks appear to tilt counterclockwise whereas the rest clockwise.

cf.

No illusion when wavy lines are homogeneously black or white.

"Wavy Fraser illusion 2"

Blocks of wavy lines are aligned horizontally, but the uppermost, third and fifth blocks appear to tilt counterclockwise whereas the rest clockwise.

cf.

Fraser illusion

Fraser illusion with slightly curved line segments

"Square-wave Fraser illusion"

Blocks of wavy lines are aligned horizontally, but the uppermost, third and fifth blocks appear to tilt counterclockwise whereas the rest clockwise.

cf.

Illusion of shifted lines

Kitaoka, A. (2007). Tilt illusions after Oyama (1960): A review. Japanese Psychological Research, 49, 7-19. PDF

"Fraser illusion of triangular waves"

Blocks of triangular waves are aligned horizontally, but the uppermost, third and fifth blocks appear to tilt counterclockwise whereas the rest clockwise.