TO DO AND TO NOTICE:

The concave "waste mold" image was produced by artist David Seagraves. While using the mold to create a bronze casting, Seagraves noticed that it had some pretty unusual properties! To see what he saw, simply follow the instructions below:

• Stand about ten feet back from this sign, close one eye and look at the face.

• Walk to the left and to the right as you look at the face. The face will seem to follow you no matter which way you move!

WHAT'S GOING ON?:

Your eye-brain system has learned that faces are usually convex, that is, curved outward. You therefore see what you expect to see. Furthermore, it is difficult to judge depth with only one eye. When you see the face with one eye closed and from far away, your brain cannot tell the face is concave.

When you ride in a car, nearby objects seem to whiz by, while distant scenery is so far off that it seems to be following you. In the same way, the nose of the face is farthest away from you, so it seems to follow you as you walk by. Since you see the hollow face as if it were protruding from the wall, this makes the entire face seem to be turning fo follow you.

 

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