Spiral illusion
Concentric circles appear to be spirals.
since 2002; access from March 31, 2013
"Kame wa mannen"*
*Turtles live long
Concentric arrays of turtles appear to form spirals.
Figure 6c of Kitaoka, A., Pinna, B., and Brelstaff, G. (2001). New variations of spiral illusions. Perception, 30, 637-646
Copyright Akiyoshi Kitaoka 2001 (uploaded September 25, 2004)
(c)Akiyoshi Kitaoka 2001; (c)Pion 2001
The international academic journal "Perception" is published by Pion Ltd.
"Neural circuits"
Concentric arrays of stars appear to be spirals. In addition, the figure appears to rotate counterclockwise (clockwise) when observers approach (leave) this figure with fixating at the center. A basic image
Copyright A.Kitaoka 1999
(c)Akiyoshi Kitaoka "Trick eyes" Tokyo: KANZEN 2002
Anomalous motion illusions --- Spiral illusion
"Tiger spiral"
Concentric circles appear to be spirals.
Copyright A.Kitaoka 2003
Spiral illusion of the Zollner illusion
"Sitting-up all night"
Concentric red lines appear to be spirals. In addition, the left "eye" appears to rotate counterclockwise while the right one clockwise. Furthermore, both "eyes" appear to expand.
Copyright A.Kitaoka 2003
(c)Akiyoshi Kitaoka "Trick eyes 2" Tokyo: KANZEN 2003
"Hatching"
Concentric arrays of dots appear to be spirals.
Copyright A.Kitaoka 1999
(c)Akiyoshi Kitaoka "Trick eyes" Tokyo: KANZEN 2002
"Songs of frogs"
Concentric arrays of dots appear to be spirals.
Copyright A.Kitaoka 2001
"Primrose's spirals"
Concentric arrays of "flowers" appear to be spirals.
Copyright A.Kitaoka 2002
(c)Akiyoshi Kitaoka "Trick eyes" Tokyo: KANZEN 2002
"Blizzard"
Concentric arrays of dots appear to form a spiral.
Copyright A.Kitaoka 1998
"Kaminari-san"*
*God of thunder
Concentric gray lines appear to be spirals.
Copyright A.Kitaoka 1998
(c)Akiyoshi Kitaoka "Trick eyes" Tokyo: KANZEN 2002
"Candy"
Concentric gray lines appear to be spirals.
Copyright A.Kitaoka 1998
"Uzumaki ampan"
Concentric gray circles appear to be spirals.
Copyright A.Kitaoka 1998
(c)Akiyoshi Kitaoka "Trick eyes" Tokyo: KANZEN 2002
Spiral illusion --- Cafe Wall illusion
"Air mail spirals"
Concentric rows appear to be spirals.
"Frog eggs"
Concentric rings appear to be spirals.
Copyright A.Kitaoka 1999
"DNA"
Concentric gray lines appear to be spirals.
Copyright A.Kitaoka 2000
"Deep sea"
Concentric arrays appear to be a spiral.
Copyright A.Kitaoka 1999
"A blood vessel"
Radial arrays of dots appear to be distorted.
Copyright A.Kitaoka 1999
"Italian spiral"
Concentric arrays of rectangles appear to form a spiral.
"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 Pion Ltd 2001 <deleted March 31, 2013>
(Originally illustrated by A.Kitaoka 1999)
Attention: This work is published in an academic journal "Perception" (see
above), which shows papers of studies on perception. I have never explicitly
transferred the copyright to the Pion Ltd, which publishes Perception,
but it is naturally accepted that the Pion Ltd has the copyright of this
work. Therefore, it is strongly recommended that those who would like to
use this figure in their papers or books should also obtain permission
from the Pion Ltd. In my opinion, although this work might be artful, this is no more than
a spiral-illusion version of the illusion of "shifted gradations"
(Kitaoka, 1998). That is, this work can be a basic figure like the Zollner
figure or the Cafe Wall figure. I thus hope that free use may be made of
this work for research or educational purposes. <deleted March 31, 2013>
Most of the figures shown in this homepage are GIF files, which are bitmap ones. This mean oblique lines or edges should be jaggy. For those who need vector files (Microsoft Word files or Corel Draw files), please feel free to contact me. Let's see illusion with the maximum amount of illusion!
reproduced March 31, 2013