Long recognized for their adroit design innovations, brothers Ronan and Erwan Bouroullec rethink the sofa with contrasting materials and a strikingly simple form. Cassette has rigorously straight lines, with an entirely exposed structure in powder-coated steel and oak plywood, leavened with deep, rectangular cushions plumped with goose down and foam fill. “In French, a cassette means a small box in which to lock up something precious. A sort of case, a cocoon,” says Ronan. “This is our message with this sofa.” Supplied by Established & Sons fully assembled, the sofa is meant to last a lifetime—as needs and environments change—and it can be taken down for ease of installation, flat storage and moving in and out of tight spaces and narrow passageways.