The Musicwriter is one of several music typewriters created to print sheet music. Some music typewriters were their own thing, whereas the Musicwriter started life as a normal typewriter before being converted to print notes and staves. You operated it by typing with the right hand and moving the carriage with the left, which sounds a bit tricky to get right—like writing music with an Etch-a-Sketch. Several typewriters served as Musicwriter root stock over the years, including the 6-series Smith-Corona and, more recently, the Olympia SG3 (an example of which can be seen in this Facebook group post). More about Musicwriters from Ted Munk in Et Cetera 109 (2015), pp. 12-15, and in this addendum collecting all kinds of photos, ephemera and type samples.