An electronic musical instrument capable of producing a performance effect resembling arpeggio. Tones corresponding to one or more depressed keys are sequentially produced from the lowest tone or the highest tone and an octave range in which tones are produced is shifted toward a higher octave or a lower...http://www.google.com/patents/US4158978?utm_source=gb-gplus-sharePatent US4158978 - Electronic musical instrument capable of producing "chord pyramid" arpeggio effects
