EML Polybox Demo

Ever since I spotted it in a Devo video, I wondered what this thing was. Basically, it allowed you to build chords from monophonic synthesizers. This excerpt from Vintage Synth Explorer describes how it works:

"Poly-Box is a pitch following variable chord generator controlled by your synthesizer and Poly-Box's own keyboard with built-in memory. Poly-Box takes a single pitch from your synthesizer and creates two banks of pitch sources. Each pitch bank contains 13 simultaneously available pitch sources at precise semitone intervals - covering an entire chromatic octave. The pitch banks may be in the same or different octaves, and can cover the range from one above to three octaves below the synthesizer oscillator."