I don't know if anyone else here is a Jean Shepherd fan, but I periodically check a fan site,
http://www.flicklives.com, where some of his old radio shows and whatnot are posted.
A cut on one of his comedy albums from the early '60s talked about a neighbor of his who bought a machine that created triangular, "greaseless" doughnuts.
It turns out that a Shep fan found the ad in Popular Mechanics that hawked these machines. The company was headquartered on Dearborn in what's now River North.
The track from the LP and the Popular Mechanics ad are both available at
http://www.flicklives.com/Glossary/tria ... donuts.htm
(Whoever scanned the ad scanned it extraordinarily large, alas.)
Neat little bit of Chicago food trivia. Has anyone ever heard of these triangular doughnuts before?