I saw this at the Michaels Camera Museum in Melbourne (Australia) today, and thought it would fit in with the theme of watch photography:(I tried to provide a link to the trip advisor page, with details about the museum, but I have too low a post count, sorry!)
Steineck ABC Wristwatch Camera, Steineck Kamerawerk. W. Germany, 1949.
The 1949 Steineck Wristwatch Camera produced 8 exposures on a circular film in special magazines.
It had a single aperture fixed focus lens with a single speed shutter.