"What is the best way to distribute materials throughout a building, so as to enclose the space, strongly and well, with the least amount of material?"
Alexander states, engineers don't have an answer to this question, but his solution is a system of load-bearing walls, supported at frequent intervals by thickened stiffeners like columns, and floored and roofed by a system of vaults. The most efficient structure will be a compression structure, which bending and tension are reduced to a minimum and a continuous structure, in which all members are rigidly connected in such a way that each member carries at least some part of the stresses caused by the pattern of loading. Openings in the walls have thickened frames, and rounded in the upper corners. (Alexander 1977)
The Trulli are limestone dwellings which are notable drywall construction, a prehistoric technique still used in the Puglia region. The persistence of traditional building techniques, with the fact that they are still inhabited today make it an exceptional historic Urban Landscape.
These settlements were identified as temporary and unstable, however their internal structure, compact and without supporting elements, remains surprisingly durable and although seemingly primitive, they are not. The Trulli is authentic in its form, design, materials, setting, and feeling and thus is an adequate example of Efficient Structure.