The Stepping Feet Illusion
The very dark red and bright cyan blocks appear to move at different speeds, creating a stepping motion like tiny feet going "tip-tap-tip-tap." In reality, both blocks move at exactly the same speed simultaneously.
This occurs because when a block crosses over a stripe of similar brightness, the edge becomes less visible, creating the illusion that movement has slowed down or paused.
The Science:
First demonstrated by Stuart Anstis in 2003, this illusion reveals how our motion detection relies on edge visibility. When edges merge with similar backgrounds, our brain assumes no motion is occurring.
Controls:
Start/Stop: Toggle animation on/off
Reset: Return to start
Speeds: Slow (0.3), Medium (0.6), Fast (0.9) pixels per frame
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