I was wandering in Baltimore, waiting between buses (to Boston via New York) with an old 120 film camera (Rolliecord). I took a photo of a store window with the street reflection mixing with the mannequin. It was 120 Tri-X film.
The way her head is in the beginning of the out-of-focus area with the blurred lights makes me think of her as “dreaming.”
So, this is a traditional twin lens (one for viewing, and one that exposes the film) camera like the Rollie, such as the Rollieflex, which was a slightly higher quality model. They were easy to carry and relatively simple. There wasn’t much to break, although the film transport (it had to manage the spacing of the images on the film) sometimes could get troublesome.
What I never understood: how to compose something in the square format finder. You generally took a photo planning a rectangular crop that was either vertical or horizontal. Thinking about cropping it from the square took some planning if you wanted to make a rectangular crop later.
An interesting place for discussions about the format, and film cameras, is Flickr.
Irving Penn, Diane Arbus, and lots of others used square format.