I've been helping some friends move. Ikea furniture reminded me of this gem.\r\n\r\n\r\n\r\nIf anyone can find the original source, I'd be greatful.
I did find this:
Good luck finding the original of that. My dad had a photostat copy of that up in his workshop well before I was born. And I’m not exactly young.
Yeah, the best I could manage was that the term “Trichotometric Indicator Support” first shows up in print around 1965 in “Machine design, Volume 37” and “Road & Track, Volume 17”. Chances are the drawing existed before that, though.
My brain hurts now.