A view of the living room, which Holtzman’s interns paved in thousands of slate tiles. Two-tone stripes on the floor run perpendicular to the stripes on the ceiling. “The stripes are a matte black, which almost creates the feeling of a coffered ceiling,” says Holtzman. The coffee table, a chunk of coal with a melted-aluminum top, was a gift from designer Jim Zivic; the Moroccan rug is from Holtzman’s childhood home—“Billy Baldwin used ones like it, and so did Florence Knoll.” A vintage Eames fiberglass chair in an Alexander Girard check sits near a 1923 Steinway with a French maid’s ruffle. “The piano is such a hideous object—it’s so big. The ruffle made it more silly.”