PURPOSE: Demonstrate an impossible figure in a dramatic way.

DESCRIPTION: The walk-in box is set up on one side of the lecture hall (or classroom) and viewed by a TV camera on the opposite side, with the view by the TV camera shown on the rear TV screen above the blackboards in the lecture hall (or on a monitor in the classroom). Students watch as the instructor "walks into" the box. A spotlight is used to illuminate the box while using the TV projector.


REFERENCES: (PIRA unknown.) See Demonstration Reference File for interesting descriptions of this apparatus, how to build it, how to present it, and some variations.

EQUIPMENT: Walk-in box with TV camera, Fresnel spotlight.

SETUP TIME: 5 min.

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