Illusion of shifted gradations
since March 3, 2005
Basic patterns
(copyright free)
The horizontal gray line appears to tilt counterclockwise (Kitaoka, 1998; Kitaoka, Pinna and Brelstaff, 2004).
References
Kitaoka, A. (1998). Apparent contraction of edge angles. Perception, 27, 1209-1219. 
Kitaoka, A., Pinna, B., and Brelstaff, G. (2004). Contrast polarities determine
the direction of Cafe Wall tilts. Perception, 33, 11-20.
Horizontal gray lines appear to tilt alternately.
p.1216, Figure 16(a) in Kitaoka, A. (1998). Apparent contraction of edge angles. Perception, 27, 1209-1219.
Horizontal gray lines appear to tilt alternately.
p.1216, Figure 16(b) in Kitaoka, A. (1998). Apparent contraction of edge angles. Perception, 27, 1209-1219.
Vertical or horizontal gray lines appear to bend.
p.1217, Figure 19 in Kitaoka, A. (1998). Apparent contraction of edge angles. Perception, 27, 1209-1219.
"Sakura-yu"*
*Cherry tea for some celebration
Vertical or horizontal pinky lines appear to wave.
Copyright A.Kitaoka 1999
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"Hurricane"
The concentric gray lines appear to be spirals.
Kitaoka, A., Pinna, B., and Brelstaff, G. (2001). Last but not least: New variations of spiral illusions. Perception, 30, 637-646. (p. 638, Figure 2a)
Copyright Akiyoshi Kitaoka 2001, reproduced March 31, 2013
registered on March 31, 2013