A house over the falls
After Fallingwater (Wright, 1936–39): reinforced-concrete terraces cantilevered from a stone core over a waterfall.
The rules it illustrates
A building should grow from its site. Shape a building to its place so that it seems to grow out of the ground: take its lines from the landscape, its materials from the region, and its plan from the life it will hold.
Destroy the box. Open the corners, extend the roofs and terraces beyond the walls with cantilevers, and let the space of the house flow outward rather than being enclosed in rooms like boxes.
The nature of materials. Let each material reveal its own character (the grain of wood, the stratification of stone, the plasticity of concrete) and design each part in the way its material wants to be used.
Where it appears in the book
In the styles Organic architecture.