like the Portland Building in Oregon and the Humana Building in Louisville , Ky. , Mr. Graves has earned a place in art history books as a seminal figure of postmodernism In a professorial tone , he rails at how developers have used some of the traditional motifs associated with postmodernism , like '' keystones , arches and Tuscan colors , for the sense of what they thought was an easy and noncommercial-looking place .