"Back in MY day...." (creeky voice) we built robots with plywood and steam engines. Back then, a PIC was used to break ice, and an oscillator was someone without direction. This look back at an old Popular Science magazine article by the Modern Mechanix blog shows the innards of a giant sloth created for the 1933 Chicago World's Fair. He moves his head, breathes and roars using a prehistoric array of bellcranks, bellows, and even a state-of-the art electric motor controlled by a remote operator.