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When the disk is spun, the colors you see are illusions. This effect was popularized in 1894 by toymaker C. E. Benham, who called his spinning disk an “artificial spectrum top."
Where: Crossroads: Getting Started
Stare at a bird’s eye for 30 seconds, then look into the empty cage. You’ll see a ghostly bird—of a very different color—inside the cage
Where: Bechtel Gallery 3: Seeing & Reflections
(Embarcadero at Green Street)
San Francisco, CA 94111
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