On Cape Cod, a Bauhaus-style house gets a sibling guesthouse on a dune facing a salt marsh and a mile-long stone breakwater. And while Provincetown is known for its progressive thinking, it still has little in the way of contemporary architecture. So the team knew it was creating something unique and special, using finishes similar to the original house–gray, taupe-y stone, and dark wood.

A pair of Hans Wegner chairs sit in the living area of the guesthouse. Couches with broad wooden armrests–which double as side tables–flank a hand-knotted rug that creates a soft island over polished concrete flooring.