Project aims to bring American art to the people in public spacesWashington crossing the Eisenhower? “Nighthawks” at the bus stop? Come August, American art will be meeting the public in public, with such possible combinations as Grant Wood's “American Gothic” on a subway poster, a Frank Lloyd Wright stained-glass window on a bus stop's digital screen, and Andy Warhol's “Campbell's Soup Cans,” a painting that critiques commercial culture, turned into a roadside billboard.