The idea seemed simple enough: Knock down a wall to combine two apartments, a studio and a one-bedroom, in a graceful prewar building on the Upper East Side. But the would-be occupants, photographer Annie Schlechter and bookbinder Russell Maret, and their architect friend Joe Serrins, had a surprise waiting: The two units were born in separate buildings that had been combined in the forties, leaving mismatching ceiling heights and a huge parapet wall between them. The budget setback turned into an aesthetic score when Schlechter and Serrins realized the opened-up space would require a small supporting wall, which, with a little imagination, could become the apartment’s visual centerpiece. All they needed was six liters of KT color 03.001 ultramarin blau paint, bought at Aronson’s. “The Yves Klein blue is totally Annie,” says Serrins of the color choice. “She had recently seen all the bright Le Corbusier colors at the Villa Savoye outside Paris and wanted to use them.” Schlechter’s peripatetic design tastes also made their way into the glossy Formica-matted kitchen—one friend said it looks like a “Lichtenstein without the bubble text”—and the Surrealist-inspired bedroom.