04121488 is referenced by 59 patents and cites 3 patents.

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 are stepped on.

The device is very easy to keep and carry, and convenient to display or perform as compared to the conventional device, as the mat is light and capable of folding or rolling into a compact form.

Title
Step-on type tone scale play device
Application Number
5/771663
Publication Number
4121488
Application Date
February 24, 1977
Publication Date
October 24, 1978
Inventor
Kakunosuke Akiyama
Musashino
JP
Agent
Biebel French & Nauman
Assignee
Nep Company
JP
IPC
G10H 5/06
G10H 1/00
View Original Source