I typed on one like this up until I got a computer in 1996. I got mine about 1950. I just got it out of its portable case and it is on display in my house, along with the thermos I had in elementary school. It was getting mildew so cleaned it up. This was a hard puzzle.
My Mother taught commercial subjects in high school. This is reminiscent of her old Remington (i think it was) which I learned to type on. She would be amazed at the ease of typing on a computer -- Copy, Paste, changing around whole paragraphs. There has been so much progress in that area --- as in so many others.
This too bring back days of learning to type and having to type to the William Tell overture to make such we got even type by a regular beat. There was no Carpal Tunnel back then.
Oh my, this does bring me back. I had an old 1930's Royal Typewriter I was learning to type on. Then many years later, I wound up working for the Royal Typewriter Co. in Hartford, CT. That's quite a few years ago. :))