In the display below you might see a transparent blue
disk moving over a field of black dots. In fact, no dots are moving,
and you create the moving blue disk that you see. There is no blue disk
on the display that a camera could photograph.
By clicking on the buttons you can change this display
in countless ways. Each click on the SLOW button slows down the animation
further. Each click on the FAST button speeds up the animation.
The BIG button makes dots bigger, and the SMALL button makes dots smaller.
The HIT button kicks the disk so it moves in a new speed and new direction.
The COLOR button randomly changes the colors of the dots. The RESET
button gives back the original display. The MORE button gives more
dots. The LESS button gives less dots. You can now experiment
and see for yourself how your perception changes as you click on these
buttons. To find out more about how you see this illusion and other
illusions, see the book
Intelligence, by Donald D. Hoffman.
Reference: C. Cicerone, D. Hoffman, P. Gowdy, J. Kim. 1995. The perception
of color from motion. Perception & Psychophysics, 57(6),