I don't know what you were up to, but somehow I doubt your 1970's were as full of design revolutionizing as Luigi Colani's. If only the 1973 oil embargo hadn't thrown the polyethylene furniture business into the furnace, I'm sure we'd all be taking down the wall of chairs for our church socials, and stacking them back up--after shaking our knees out a bit--at the end of back-to-school night.
Or maybe we would've wedged into these plastic puppies. I can't get to it right now, but in Vitra's Kid Size exhibition catalogue, there's a vintage photo of a daisy chain of kids sitting at their Der Colani molded polyethylene chair/desks. [Despite what the original of this image shows, the chairs were on the floor, not the wall, in Delft's Colani retrospective.]
While it's hard to stack just one, you have to start somewhere. Twentytwentyone calls this the Zocker chair, and their orange example is 150 pounds, or $US1 million.
Werke, 1970's - Luigi Colani [colani.de]
"Der Colani" chair by Luigi Colani, The IDE Virtual Design Museum [tudelft.nl]