Gymboree-style, built-up, modular play structures wrapped in padded vinyl are so commonplace now, it's hard to imagine how unusual Mitsuru Senda'a Pokotto [ポコット] play structure might have looked in the early 1970s.
The Japanese architect and playground designer created a series of product-scale play structures for the manufacturer Kotobuki, but I can't figure out if the Pokotto was one of them. In fact, I can't find anything at all about it.
The only images I can find are from an in-house publication of Senda's firm, the Environment Design Institute, on the awesome web archive Architektur für Kinder. And the only mention of Pokotto is in Senda's 1992 monograph, Design of Children's Play Environments, where it's actually translated as Pokot.
Which seems wrong. Because I think pokotto is what a kid's head does when it pops out of one of those holes like a prairie dog. PoKO...to. But anyway, I'm throwing it out there, and we'll see if anything pops up.
Check out a whole pile of interesting Mitsuru Senda playground designs at Architektur für Kinder [architekturfuerkinder.ch]