Contrast in Shape

How objects and colors appear is highly dependent on their context. The structural and spatial variables of a scene can influence appearance and perception. The following optical illusion demonstrates how we are sometimes fooled by our eyes.

Instructions: The diagram below features two circles with different surroundings. Would you believe that the two circles are identical?

Other Illusions:
Blind Spots
Blink Effect
Bordering
Chromatic Adaptation
Chromatic Adaptation
Color Blindness
Crispening
Dither Dots
Dithering
Fill Patterns
Opponent After-images
Optical Art
Shape Contrast
Simultaneous Contrast
Simultaneous Contrast
Value Contrast

Other fun stuff:
Free 3D Screensavers
Color Playground
Dimensions of Color
3D Color Puzzle