Optical illusions

Below are free to use, class-friendly printouts that provide an optical illusion and an explanation of their behavior. These were originally distributed by ARVO at the USA Science and Engineering Festival. Use them as part of an Optical Illusion themed outreach event

Cone fatigue

Can you make this red and green image change colors?

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Negative afterimage

Turn this black and white image full color by simply staring at it.

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Blind spot

Learn how to make the black spot on this image disappear by closing one eye.

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Spheres and mouse

What color are the spheres? Where is the mouse?

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Lines and blocks

Are the horizontal lines straight or crooked? Are the two blocks the same color?

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Circles and Dots

Are the orange circles the same size? Also, how many black dots are there?

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Monsters and green lines

Which monster is larger? Which green line is longer?

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Rotating illusions

Are the circles still or rotating?

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