In the category of the arts of form the single work is to be received in its entirety and integrity as form. The whole, however, may be resolved into its parts, and the individual details may be interesting in themselves. Thus into decorative patterns are introduced elements of meaning which attach themselves to the world and experience external to the artist. Many ornamental motives, like the zigzag and the egg-and-dart, for example, had originally a symbolic value. Sometimes they are drawn from primitive structures and fabrics, as the checker-board pattern, with its likeness to the plaitings of rush mattings, and the volute and spiral ornaments, which recall the curves and involutions of wattle and wicker work. Again, decoration may employ in its service details that in themselves are genuinely representative art. The frieze of the Parthenon shows in relief a procession of men and women and horses and chariots and animals. The sculptures of Gothic churches represent men and women, and the carvings of mouldings, capitals, and traceries are based on naturalistic motives, taking their designs from leaves and flowers. The essential function of ornament is to emphasize form and not to obscure it, though nowadays in machine-made things a kind of pseudo-embellishment is laid on to distract attention from the badness and meaninglessness of the form; in true decoration the representative elements are subordinated to the formal character of the whole. The representative interest may be enjoyed separately and in detail; but finally the graphic purpose yields to the decorative, and the details take their place as parts of the total design. Thus a Gothic cathedral conveys its complete and true impression first and last as form. Midway we may set ourselves to a reading of the details. The figure of this saint on the jamb or the archivolt of the portal is expressive of such simple piety and enthusiasm! In this group on the tympanum what animation and spirit! This moulding of leaves and blossoms is cut with such loving fidelity and exquisite feeling for natural truth! But at the last the separate members fulfill their appointed office as they reveal the supreme function of the living total form.