Anti twisting mechanism with fischertechnik - Dirac belt trick

How can one supply a rotating lamp with energy WITHOUT a slip ring? As recently as 1971 Dale A. Adams found a mechanism although Indonesian candle dancers knew the solution for generations. We show a fischertechnik models of Adams' mechanism and another one that is easier to understand. We also briefly comment on Dirac's belt trick and the rotation group SO(3). http://math-meets-machines.de  #fischertechnik #mathematics #topology #spin #physics