The Reverse Phi Illusion
You'll see continuous forward motion even though nothing actually advances. The sequence alternates between regular photos and their inverted (negative) versions, creating motion without progression.
This occurs because our motion detection system responds to brightness pattern changes rather than actual object displacement. The contrast inversions create perceived motion in one direction despite the back-and-forth jumping.
The Science:
This "four-stroke motion" effect reveals a conflict in visual processing. Motion detectors indicate continuous movement while feature tracking recognizes back-and-forth jumps, demonstrating how motion detection operates independently from position tracking.
The Sequence:
Four frames cycle: two regular images, then the same images in negative. This pattern tricks our visual system into perceiving smooth motion despite the contrast reversals.
Controls:
Start/Stop: Toggle animation on/off
Reset: Return to first frame
Speeds: Slow (1/2), Medium (1/4), Fast (1/8) seconds per image
Ready