“Frank Lloyd Wright came tantalizingly close to redefining the Washington skyline. The master architect was commissioned to design a $15 million complex at the corner of Florida and Connecticut avenues. Two drawings from 1940 — which appear in an exhibition opening today at the National Building Museum — show how the neighborhood above Dupont Circle could have become a stunning landmark equal to New York’s Rockefeller Center.” So what happened? Wright’s self-importance apparently rubbed the Washington bureaucracy the wrong way, and what could have been a major urban initiative died at the hands of the local zoning code. All of which explains how Wright came to build a major skyscraper in the middle of an Oklahoma prairie.