RickWartzok built this thing from a block diagram by WardCunningham. It used an analog four quadrant multiplier and other AnalogStuff that has faded from memory. It was suppose to display an orb that wiggled and pulsed with the average volume level on each of the four channels of a quadraphonic recording. The goal was a display that was more ergonomic than four VU meters in a row. It was never put into service. But it did draw some pretty incredible pictures in prototype form. The best images came from an fm stereo when tuned to interstation noise.