A one piece extrusion for use in the manufacturing of structures including structures such as frames, wall partitions, display boards, signs, covers, filters, screens, mesh, window sash and window-like structures, such window frames, window sash and other structures and methods of making such structures...http://www.google.ca/patents/US4233790?utm_source=gb-gplus-sharePatent US4233790 - Extrusions and building structures
