This story was originally published in Dwell’s July/August 2014 issue.

It was the grain of sand that became a pearl. CxMxD, a team of three New York City–based designers, hit upon the idea of a faceted circle while conceptualizing their entry for Add-on’13, an affordable-housing competition in Cape Cod, Massachusetts. That circle evolved into an adaptable five-sided structure called Oyster House, which design lead Christopher Lee, visualization designer Mengyi Fan, and graphic designer Dungjai Pungauthaikan envision as a way to build for high density and low impact.

The rooms are arranged from most public to most private and face outward to maximize borrowed space from the outdoors. “A circular arrangement [means] you’re able to modify and orient the house to take advantage of the landscape,” says Lee. “And it’s superefficient in terms of surface area.” At 700 square feet, the pentagonal Oyster House—which will be built with structural-insulated panels and clad in shingles—has less surface area than (but the same floor area as) an equivalent rectangle or square, meaning lower heating and cooling loads.

CxMxD has also envisioned some slight changes that would allow the house to comply with the Americans with Disabilities Act (ADA), something they’ll address in their next step: building and testing the prototype in a Cape Cod town. “Wellfleet has a rich history of modernist case study houses,” Pungauthaikan says, “and we’re interested in continuing that legacy.”

A Space-Efficient Affordable Housing Prototype