Knock Twice for Offbeat Design Studio O+A, a San Francisco design firm, is expert in nontraditional offices, having created workplaces for Facebook and PayPal. So imagine what kind of office it would make without a client breathing down its neck. The answer is Bureau, a 375-square-foot space at 445 Natoma Street, which O+A furnished on a lark to resemble a living room where work gets done. What makes Bureau truly eccentric is that it is also a store. Most everything there, including O+A's modular Edge desk ($6,465, shown) and sticker sheets printed with irreverent remarks ($2), is for sale, even though the shop does not keep regular hours. "You can knock and we'll let you in," said Verda Alexander, who founded the firm with Primo Orpilla. "Of course, it's going to be completely changed," Ms. Alexander said. She wasn't ready to divulge the next theme, but said, "Our designers get a kick out of pulling out their Square Readers and swiping the credit cards." Information: (415) 908-1880 or o-plus-a.com.