Patent Appeal No. 8502. October 7, 1971. Alvin Guttag, Washington, D.C., attorney of record, for appellants; William T. Bullinger, Washington, D.C., Sheldon F. Raizes, Wilmington, Del., Cushman, Darby Cushman, Washington, D.C., of counsel. S. Wm. Cochran, Washington, D.C., for the Commissioner of Patents; Fred E. McKelvey, Washington, D.C., of counsel. ON PETITION FOR REHEARING PER CURIAM. The Patent Office petitions for a rehearing or modification of our decision, handed down June 10, 1971. The