Klaus Biesenbach lives in an all-white, 550-square-foot high-rise apartment that contains little more than a table, a bed, a couch and two or three chairs. His favorite feature is the view from his window, which he photographs every day and posts to Instagram for his #window23 project. “It’s a calming place because there aren’t many distractions,” he said. “That’s what makes the window so important. How can you compete with the world?”