Your walls needn't be marked with nail holes to hang your favorite grouping of framed work. When you install a picture rail -- a strip of molding from which hooks and pictures can be hung -- you can carefully display your artwork in a variety of compelling ways. The rails are available at most lumberyards and home centers. A crisscross pattern of cord, used here to show off 19th-century seaweed prints, is quite complex-looking but not difficult to re-create: Start with the bottom row, then work your way up.