"A small, metallic gold ball just over 2cm in diameter. Place it on the plastic channel which should be slightly sloping, and you would expect it to roll down in the normal way. Well, this ball does roll, but it does so incredibly slowly. To an audience, it seems baffling why it should roll down a slope apparently in slow motion. You can pick the ball up, and it seems heavy, possibly solid. No clues if you shake it."
Get a ball for yourself at Grand Illusions in the UK>>