Genesis of the “Golfball” Selectric

Article note: It's a 2011 article, and the start is a little screed-y, but it is a _fascinating_ look at the various convergent type element designs. I was aware of the Blickensderfer and TTY cylindrical style, and that IBM licensed the Marx toy for some of how it manipulated the cylinder, but there are a number of details I hadn't seen elsewehre, and I'd never come across the various precursor convex type element designs.