What is the boundary between indoors and out? Designed with the philosophy that the comfort of outdoor openness is psychologically freeing, the Atelier Tenjinyama in Japan is a study in modern primitivism.

Four reinforced concrete walls are mounted on a dirt floor, and covered with a transparent ceiling of shatterproof glass. Tall windows slice through the concrete, opening the bunker up to its urban surroundings.

"This atelier is in the environment where an evening of the summer has many thunderstorms, winter has fine weather and strong dry wind blows in," Ikimono Architects writes.

It's a dramatic effect when snow and rain gather above head on glass panels. But the elements might take a toll—aside from opening an office-dweller's mind—when nature calls. An umbrella is always present, open, in the office, for when ducking out to the restroom, which is through an open-air corridor.