The Prison Guard.

For a small group only. Make a square representing a prison on a piece of paper, not joining the lines at the corners however. Let “P” represent a prisoner in the center of the square. At three of the corners let “G” represent guards. The story is that the prisoner escaped in spite of the guards, that there was a guard at this, and this, and this gate, pointing with your pencil to the three gates at which are stationed guards. Ask how in the world he could have escaped.

Invariably someone answers, “Why he could have gone through this gate,” and puts the tip of his finger on the unguarded gate. Your pencil is resting carelessly on the paper. At the crucial moment you hold it poised and when the answer comes and the finger points to the unguarded gate, your pencil comes into action with a swift rap across the knuckles as you exclaim in surprise, “Oh no! I am guarding that gate!”