“Architecture has entered another of its periodic bouts of fascination with impermanence. Maybe it’s the anxiety produced by doomsday predictions about the state of the environment and, lately, the economy. Maybe it’s the quicksilver quality of digital culture, closer in character to sand or water than bricks and mortar. Whatever the source, architects are playing up the idea of temporariness, and even finding solace in it, to a degree not seen since the 1960s and ’70s.”