Ping WW

Thanks for that. Seen them a few times in my forays. They look intriguing, if a little inefficient in some ways, despite the enclosure-of-space efficiency of a sphere. But maybe you can store some stuff through a trap door under the floor, etc., and get bigger ones and maybe some connected with an enclosed go-between... a modular "humster" arterial network that expands with your needs.

I've just about seen every treehouse that's out there that's online, and my favourites probably include the more classic La Cabane Perchee-- apparently from my old home province (Quebec) too (and also Pierre's):

Make me a composting worm. :)