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Witchcraft, Min...!


Not much rolling around of the ball when the cup is lifted. Magnetic trickery?

My solution.

There are, of course, three balls, one in each cup. The balls are steel or have a steel insert so that they will be attracted to a magnet. Normally the balls are held in the cups by a weak magnet or a light friction fit (foam lining etc).

Underneath the table are three pivoted arms each with a strong magnet at the free end. The end of one of the arms with the magnet is raised and lowered by a mechanical system driven by the array of vertical pegs so that the desired magnet is raised into contact with the underside of the table. The table top is actually quite thin so that when a magnet is raised up against the underside of the table the magnet attracts the steel ball and holds it in position on the table as the cup is raised.

The sequence of movements is controlled by the pattern of the vertical pins so eventually you could work out the repetitive pattern of ball presentations.

I think that a strong magnet is involved because the balls show no tendency to roll around on the smooth table surface. The thick edge of the table hides the mechanism below.

Still a neat mechanism though.