In 1979 Levin and Roy reported on interlocking directors at 797 corporations in 1970 where the board of directors ranged from 3 to 47 members, with a mean size of 13. Only 18% of the 8623 directors were on more than one board, though the mean number of interlockers for a corporation was 8. The components of the graph were 62 isolated boards, four pairs of corporations interlocked by one or more directors, a triad of interlocked corporations, and the greater component of 724 corporations. For an arbitrary pair of corporations in this component the median path length was 3. Levin and Roy tested the graph for cut points and failed to find any with their search starting with corporations with large boards. In a study of clustering in the graph, Levin and Roy demonstrated the use of a bipartite graph with corporations listed on one side and directors with multiple seats on the other. The clusters become evident in a physical model using elastic bands and paper clips. The directors and corporations are listed arbitrarily to begin and the elastic bands placed as edges of the bipartite graph. Then a perusal of the elastics may suggest a re-ordering on one side or the other with the elastics slightly less tense. After some iteration this procedure reveals a cluster structure in the bipartite graph.