the structure's walls are made of local desert rocks, stacked within wood forms, filled with concrete - colloquially referred to as "desert masonry". wright always favored using the materials readily available rather than those that must be transported to the site. in wright's own words: "there were simple characteristic silhouettes to go by, tremendous drifts and heaps of sunburned desert rocks were nearby to be used. we got it all together with the landscape…" the flat surfaces of the rocks were placed outward facing and large boulders filled the interior space so concrete could be conserved.