Imagine trying to learn how to use this. It’s a music typewriter from the 1930s.It was first patented in 1936 (14 keys) by Robert H. Keaton from San Francisco, California, . Another patent was taken out in 1953 (33 keys) (view 1953 patent) which included improvements to the machine. The machine types on a sheet of paper lying flat under the typing mechanism.
From Music Printing History archives.