Very good used condition with original English instructions!
Invite a child on stage and hand them a miniature traffic light (made from wood) with a hole drilled through as well as a piece of rope.
Both are ordinary. The rope is threaded thru it and the kid holds the rope horizontally. You move the stop light up and down the rope and suddenly it stays suspended in the middle of the rope. This you repeat several times. all can be examined and no matter how hard somebody tries; they are unable to recreate the feat.
Very early David Ginn item, now hard to find!
