Cocoon or coffin? The transformation inflicted on Nagasaki by the United States’ Fat Man in 1945 shuttered more than six years of war. In drastically different styles, artists Tom Sachs and Paul Fryer revived Fat Boy as personal sanctuary. For the minimalist, there is Fryer’s “Rehabilitation,” a wood and steel replica, complete with a bed, lamp and good read. Sach’s work, by contrast, recalls 2001: A Space Odyssey. His “Sony Outsider (Gajin),” is fashioned from plexiglass and tricked out with a bed, urinal, washbasin, TV/DVD player, and Dolby stereo. The idea that the bomb refreshes, or that only within the most daunting fortress is there a reliable sanctuary, are the ironies captured by both. Yet their coffin-like claustrophobia confirms the limitations of such thinking.