I don't know the English word for 'pluche' - the synthetic fiber out of which teddy bears are made.
So we take this material, make it a bit bigger to cover entire walls with it; we make sure the fibre is strong but very soft and nice to touch.
We dig a hole in a plot of land, in which we drop
our very large toroid made out of concrete. [see pic 1 for the exact shape of the toroid]. A second layer inside the toroid is made out of strong rubber sheet, which is suspended to the wall of the outer toroid. So that you have a kind of trampoline.
Now we cover the interior wall of the interior rubber toroid with the adult teddy bear material - fresh green, mildly pink, pastel colors, have your pick.
Voilà, you can walk for hours inside of this house, you can tumble, jump, bounce - all this inside a large tunnel, you know, with the typical 'eternal' tunnel effect as seen in computer games.
In the steep parts of the tunnel, you will exprience the feeling of being able to fall into emptiness. And you can jump or roll - you will be catched safely by the rubber and the pluche!!
It must be a fantastic regressive experience for adults!
The inside of the toroid house is full of charming light, which can be dimmed and colored.
[you enter the house via a small staircase on top of the toroid, which is entirely underground].
-Mind you, its a kids house for adults, with a bit of a space, 'techno-feel' to it. [inspiration comes from the large classic toroid space-islands imagined in the past, pic 2].
-Further inspiration comes from the laboratory building seen in the classic SF-movie 'The Andromeda Strain' [picture 3].
-So we have a bit of the same 'clinical' techno-cool, but then in a 'warm', teddy-bearish version, ehe.