The lines of Saul Steinberg’s mind

A new exhibit at the Art Institute exemplifies the genius of the 20th-century artist. Saul Steinberg liked to call himself "a writer who draws," but during the 20th century few draftsmen could approach his inventiveness. In his drawings, Steinberg's lines seem to reinvent themselves as they progress, zigging when you expect them to zag, or disappearing abruptly just as they appear to be gathering steam.…