The structural solution is quite simple: a pair of two-story wishbone- or Y-shaped concrete piers supports a flat concrete roof sheltering a glass box like a giant concrete umbrella. Freed from the task of supporting the roof, the skin becomes open and light, with a simple grid of concrete piers spanned by sliding-glass doors wrapping a wide-open interior. (The wishbone piers don't do all the structural work: round concrete columns placed just inside the window frames, and frameless glass corner windows make the skin feel delicate and almost nonexistent. Although the giant Y-shaped piers and spacious interiors give the house a strong identity, they play a supporting role to the tropical sunlight and spectacular views that fill wall-to-wall windows in every room.