Architects Leslie and Julie Dowling, twin sisters and Michael Graves protégées, created this 1,000-square-foot, single-story home by linking two flat-roofed pavilions together in the shape of a T. The design of this Sonoma County home was inspired by Philip Johnson’s 1949 Glass House in New Canaan, Connecticut.  Photo 15 of 16 in Guide to 7 Main Types of Roofs and What You Need to Know About Them from Pools to Dive Into