Answer #51

The answer is (d): the "triangle" is formed using three orthogonal square rods, as can be seen in an mpeg video by clicking your mouse on the photograph below.

This is but one of a large number of similar illusions, probably modeled after the Escher spiral staircase. Another is the walk-in box, shown in a photograph below.

Click here to see Gwen walk into or out of the box. For further information regarding this illusion see references to our demonstration O4-35: WALK-IN BOX.

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For questions and comments regarding the Question of the Week contact Dr. Richard E. Berg by e-mail or using phone number or regular mail address given on the Lecture-Demonstration Home Page.