The display below is an interactive demonstration of structure
from motion.
By clicking on the buttons you can change this display
in countless ways. Each click on the SLOW button makes the dots stay
on a little longer. Each click on the FAST button makes the dots
stay on a little shorter. The BIG button makes dots bigger, and the SMALL
button makes dots smaller. The COLOR button randomly changes the
colors of the dots. The MORE SLANT button increases the slant of
the axis of rotation. The LESS SLANT button decreases the slant of
the axis of rotation. The MORE TILT button increases the tilt of
the axis of rotation. The LESS TILT button decreases the tilt of
the axis of rotation. The AXIS button is a toggle that displays or hides
the axis of rotation. The RESET button gives back the original display.
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
Visual
Intelligence, by Donald D. Hoffman.