1
Kakunosuke Akiyama: Step-on type tone scale play device. Nep Company, Biebel French & Nauman, October 24, 1978: US04121488 (59 worldwide citation)

A step-on type tone scale play device has a flexible mat within which is arranged a plurality of flexible switch elements in accordance with a tone scale and is adapted to produce corresponding music sounds when marks configured on the surface of a mat to indicate the position of each switch element ...


2
Step-on type tone scale play device. Nep, December 6, 1978: GB1535008-A (4 worldwide citation)

1535008 Electronic musical instruments NEP CO Ltd 7 March 1977 [8 March 1976 22 May 1976] 09419/77 Heading G5J A particular tone is voiced at 8 when a switch under one of the marked areas of a flexible mat 4 is closed by standing on the corresponding area; each switch comprising an insulating cushio ...