The 99th Street plan is shown here. "Layouts were driven by the most basic design principles: hyper-efficient floor plans that minimize circulation with singularly-located plumbing stacks," Lehrer says. "The roof slope and roof-site drainage was also made as simple as possible. The continuum of public to private space was carefully orchestrated."  Photo 11 of 11 in Vibrant Affordable Housing Prototypes in Los Angeles