Freezing Rotation
Freezing Rotation — 2026, generated SVG, dimensions variable · Motion · Moving
After Max Dürsteler, 2006
Does the pinwheel keep the same speed?
Does the pinwheel spin at a constant speed the whole time?
How to look: Watch only the center pinwheel, not the ring around it.
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Reveal the answer
It never changes speed. Only the motion of the surrounding ring changes.
↑ The mechanism, made visible.
Notes — why it looks that way
What is happening
The center pinwheel spins at the same speed from start to finish, no exceptions. Only the ring of dots around it moves back and forth, repeatedly. Watching only the pinwheel, it should still appear to slow down, or nearly stop, at times. It looks frozen at the moments when the ring is moving fast in the same direction as the pinwheel.
Why it looks that way
Your visual system does not measure rotational speed in isolation — it relies heavily on the difference relative to its surroundings, i.e. relative motion. When the surroundings move faster in the same direction, the pinwheel feels like it is “lagging behind” or standing still relative to them. When the surroundings move the opposite way, the pinwheel feels like it is spinning fast. It is the same family of effect as feeling like you are moving when you are sitting still on a train and the train next to you pulls away.
How to check
The answer view marks where one blade of the pinwheel pointed at every one-second interval. The intervals are all equal, showing that it advances the same angle in the same time, every time. Press pause to stop the motion, and cover the ring with your hand to watch the pinwheel alone — the apparent change in speed nearly disappears.
See the illusion where motion stops after it ends
First described
After Max Dürsteler, 2006
Source: Dürsteler, "The freezing rotation illusion", Progress in Brain Research 171 (2008)
Winner of the 2006 Best Illusion of the Year Contest. The paper followed in 2008.
Media — images and data
- OG / X (1200×630)
- Instagram square (1080×1080)
- Shorts / Reels vertical (1080×1920)
- Answer image — landscape (X)
- Answer image — square (Instagram)
- Answer image — vertical (Shorts)
- Post drafts (JSON)
Free to use for non-commercial purposes such as classes, school projects and blogs, with a link back to this page as the credit. Commercial use is not covered
Every figure is generated here from the phenomenon itself (re-implemented). The principle of "a center rotating at constant speed surrounded by an oscillating ring" is re-implemented here from scratch as a pinwheel and a ring of dots. No figure, video, or code from Dürsteler is used.