For this Soho residence, the New York architects combined two stacked apartments with a new rear extension. The resulting duplex expands as you move through it. Starting with a low entry, they gained ceiling height by dropping the floor of the rear extension. This further created multiple levels for gardens: a sunken terrace outside the living room, an arboreal backyard above, and a green roof off the master bedroom. , the treads of the new stair cantilever from a bank of cabinets. And lastly, a chimney with indoor and outdoor fireplaces anchors the glass wall of the living room.