P3D Phantogram

[roberts@xxxxxxxxxxxxxxxxx (John W Roberts)]

Not quite the same, but perhaps a related phenomenon:
At the Exploratorium in San Francisco, there's an exhibit that
shows (if I recall correctly) one or more rotating wire-frame models,
illuminated by two colored lamps, with a wide baseline between the
two lamps. The light from the lamps is cast onto a screen, causing two
colored shadows of the model(s) to appear on the screen. When the screen
is viewed with anaglyph-type glasses with two different color lenses,
a single "3-dimensional shadow" appears.

(To those who have been to the Exploratorium: did I describe it correctly?)

John R


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