At the booth of Pan American Art Gallery in Dallas were some Silver Clouds by William Cannings, clearly based on the ones Andy Warhol made in 1966. Instead of being filled with helium, Cannings’ clouds are made of metal and hang on wires. Gallery director Cris Worley explained that Cannings, an Englishman who now lives in Lubbock, makes the things out of "inflated aluminum" -- welding together sheets of metal, heating the resulting object in a kiln and then inflating it. The clouds are $750 each.