Sculpture: Bolt Ahoy

Some seem to fly through the air like a jet taking off. Some dangle from the ceiling and seem to float, like a yellow submarine, at ankle, knee-or eye-level. Yet none of these ever actually move, for they are not boats, not planes, but sleekly minimal bolts and beams cantilevered into a startling semblance of motion by Manhattan's Robert Grosvenor, 31. "I like sculpture to be a kind of quick thing, like what we see out of train windows," says Grosvenor. "I like things I've seen very fast and I don't know what...