"The sites were extremely constrained; a circumstance we really welcomed," Lehrer says. "While some streets were in better shape than others, the basic urban housing fabric is intact. Our work is precisely to respect the existing fabric, understanding typology and what makes the streets coherent. Just blending in seamlessly would neither honor nor energize the street. It required some invention, palpable freshness and optimism." The 99th Street house is shown here.  Photo 7 of 11 in Vibrant Affordable Housing Prototypes in Los Angeles