TOPIC:

ID Code: O4-22
Purpose: Classic Cornsweet illusion with circular rotating discs.
Description: The disc shown above is painted half black and half white, with the pattern shown in the photograph. A disc without the pattern would appear a uniform shade of gray when rotated by a high-speed rotator. The pattern above, however, produces different shades of gray, the lightest inside and the darkest outside, due to the transition in the pattern. When the junction is covered by a ring, the two segments look the same shade of gray (which of course they are).This effect is due to the fact that the eye responds more strongly to rapid changes in black/white density (the sharp edges) than to smoother changes.Another disc is available that includes four junctions, seen above at the right.
Availability: Available