No. 1.—Build Your Own Analog Computer.

(Click to enlarge.)

BY FOLLOWING THESE simple steps, you may easily construct Dr. Boli’s Celebrated Prognostication Engine, a special-purpose computer that foretells the future with astonishing accuracy.

1. Download and print the full-size version of the dial and spinning arrow.

2. Paste the printed page on a piece of heavy cardboard; then cut out the dial and the arrow.

3. Push a pin or tack through the center of the arrow.

4. Push the pin or tack, with the arrow on it, into the center of the dial.

To use your Prognostication Engine, simply think of a question (it is not necessary to speak it aloud) and give the arrow a good spin. The correct answer may be read where the arrow stops.

N.B.—If the arrow stops on the line between two answers, you may assume that both answers are correct.