TOPIC:

ID Code: O4-24
Purpose: Classic distorted face illusion.
Description: Stare at the spiral disc at a fairly close distance (a few feet is best) for about thirty seconds while it is rotating at about one revolution per second. Then stare from a close distance (a couple of feet) at your neighbor's face. A distortion of the face will be perceived due to the optical channel activated by the rotating spiral.
Availability: Available