This illusion was developed by Akiyoshi Kitaoka (2005), a psychologist in Kyoto, Japan. Because this illusion creates an illusion of motion from a static display, you can see the motion in static figures. You can also visit Dr. Kitaoka’s Web site to view not only this illusion but many other striking motion illusions that occur with static displays. The rotating snakes illusion is based partially on the earlier Fraser-Wilcox spiral staircase illusion (Fraser & Wilcox, 1979), which you can see on ISLE 8.16, as well. Kitaoka, however, has multiplied the effect. If you look at the center of any particular “snake,” you can see that the snake you are looking at is stationary. However, you will notice that the rest of the “snakes” are in motion. The motion is illusory—the figure is completely static. You can test this by changing your gaze and looking at another “snake.” Now the new snake is stationary and the one you were just looking at appears to move. And if you are looking at the illusion on paper rather than on a computer screen, you know it is impossible for that paper to move in the way you are perceiving motion. If you are viewing the illusion on a computer screen, consider printing out the illusion to convince yourself that the motion is illusory.
See the text for an explanation of the illusion.
In this activity, you can not only view the illusion but change various parametes of the illustration to see how they impact the strength of the illusion.
To see the illustration in full screen, which is recommended, press the Full Screen button, which appears at the top of the page.
Below is a list of the ways that you can alter the illustration. The settings include the following:
Colors: select from some preset color sets to see how they
alter the strength of the illusion. Blue/Yellow are the original colors.
Brightness: change the brightness of the illustration.
Show One Snake: show just one of the spirals, what I am calling a snake.
Overall Size: change the overall size of the illustration.
Change Snake Size: change the size of the individual spirals (snakes) without changing the overall size of the illustration.
Pressing this button restores the settings to their default values.