Architects have long envisioned housing prefabrication as a means to improve design and reduce costs. Frank Lloyd Wright designed his American System-Built homes, seven models of modest houses using precut materials intended to be affordable, between 1912 and 1916; his Usonian houses, about 60 middle-income, L-shaped single-story houses without basements or attics and using simplified construction techniques, in the 1930s; and his mobile home in 1955. Stimulated by Bauhaus thinking, architects thought prefabs were the ideal way to rationalize the building process, achieve economies of scale, and bring good design to the masses. But the manufactured housing format that would win widest acceptance was the trailer. Architect-designed prototypes seldom have been reproduced at scale.