As the Pilaster is used structurally in order to give support, so its treatment in interior decoration must conform to architectural requirements, and the decoration should be symmetrical on a central axis and vertical in direction. When flutes are employed to decorate the pilasters, they should be unequal in number--seven being a favourite number. The flutes may be further decorated by cabling, though this should extend to only one-third of the height. The cabling can be elaborated into a series of husks which may arise from the base or be pendant from the top of the pilaster. In either case the general rule must be observed that the cabling shall occupy only a third of the total height. _Panelled Pilasters_ Sunk panels are also used for decorating pilasters. They cover about half the width, and are moulded at the edges. In some instances, notably in pilasters of the Early French Renaissance, the panel is broken in the centre by the introduction of a smaller circular or lozenge-shaped panel. Sometimes the panel is adorned with floral or other detail, and this should be symmetrically arranged on a central axis. For this purpose the undulate stem should never be employed. Such detail requires a start at the base and a definite finish at the top of the pilaster, but for the rest, it may consist of the same unit repeated, or of two alternating units. In order to emphasise the structural character of the pilaster it was customary to introduce features in the form of mouldings, vases and labels. _Capitals and Bases_ The capitals and bases of pilasters should be in harmony with the other decorations used. The usual capital of the Italian Renaissance is a modified Corinthian type, and this is quite suitable when the pilaster has plain or decorated panels, but when flutes are employed on the pilaster a more ornate capital is desirable. In the latter case a composite form in which the Doric abacus and enriched ovolo figure together with a row of stiffly-arranged vertical leaves, could fitly be used. The Ionic type would also be suitable; when the base of the pilaster is decorated, the lowest detail of reeds of the principal torus may be bound with cross ribbons. [Illustration: No. 208. Pilaster Treatment. French Renaissance.] [Illustration: No. 209. Treatment of Pilaster Capital, with Vertical Emphasis.] _Treatment of Panels_ Panels and enclosed spaces have no structural significance, and therefore in the treatment of them attitude alone has to be considered--that is to say, the only question is, as to whether the surface to be decorated is in a vertical or a horizontal plane. In the decoration of a panel in a horizontal plane, since it is not desirable to mark any one direction, the detail may radiate diagonally or diametrically from a centre. If, however, in the case of a ceiling, details are employed in the angles formed by the walls, these should grow towards the centre of the ceiling.