Believe it or not, the "flippy" was actually patented in 1974. US3932895A
...and let's not forget the 3" CF2 diskettes--designed to be flippies right fron the get-go. BASF certainly marketed 5.25" flippies: https://cdn.instructables.com/FWP/3D0Z/GXL5XZ3U/FWP3D0ZGXL5XZ3U.LARGE.jpg --Chuck
