an intricate knot tied by Gordius, the king of Phrygia, and cut by the sword of Alexander the Great after he heard that whoever undid it would become ruler of Asia
a device invented by Edison that gave an impression of movement as an endless loop of film moved continuously over a light source with a rapid shutter; precursor of the modern motion picture
a radio receiver that combines a locally generated frequency with the carrier frequency to produce a supersonic signal that is demodulated and amplified