Fun stairs

I'd love to know why all stairs don't have a slide built next to them. This is great fun.

Here's the writeup from daddytypes.com:
Minimalist architect Alex Michaelis first made news when he bought a 4,000-sf vacant lot in London for £750,000. (Apparently, several centuries of concentrated building tends to deplete a city's supply of vacant lots.) Then, because local zoning boards restricted him from building anything higher than the 6-foot high wall around the property, [??!?] he designed the whole house to be underground. And incredibly eco-friendly, from the self-sustaining water and heating systems to the insulated walls, solar panels, and grass roof.

Oh, and it's beautiful, modern, and light-filled, thanks to carefully positioned windows, lightwells, skylights, reflections off of the swimming pool, and thanks to painting every built surface a blazing white...

Oh, and it's a kid's paradise, with a climbing wall, a built-in slide, play terraces, and wide open playspaces for his three (four?) kids. Oh, and the pool's optimized for kid-sized swimmers, not adults. It all adds up to make them the most popular hippie mole people in their school.