In arms in relief, whether in large mural decorations or in the minute workmanship of a seal, contiguous spaces, which in flat painting would be considered divisions of the same plane, are distinguished from each other by sinking the surface in parts or by means of diapering. The quarterly shield of Henry IV on his great seal (Fig. 2, p. 18) has the field of the English quarter sunk so that the edge of the French quarter being higher takes light or throws a shadow which defines the space. Additional emphasis is given to ordinaries by strongly bevelling their edges which then reflect light in the same way. And diapering, which has been already referred to, may have the effect of raising or lowering the tone of the decorated surface, according to the amount of light it reflects or of shadow that it includes. The mantling that occurs in sculpture, especially when done in wood, does not hesitate to go to the fullest extent in the direction of free ornamental treatment, and in thus seizing upon the decorative possibilities of its so lightly fettered character it may form a connecting decoration between the constituents of an heraldic scheme which might otherwise have a certain effect of spottiness. The pose of the heraldic elements of the design may also be made to help materially the general unity of effect. Thus the helmets of a series of armorials may be faced towards a central point, such as the altar in a church, or the hearth or the daïs of a secular apartment. Shields may be inclined in a common direction with similar intention and all the heraldry have definite relation to its surroundings. It should be remembered, however, that in thus posing the elements of a series, a shield must be treated as a whole, and the contents must not be altered in sympathy with the direction of its regard. [Illustration: FIG. 198.--Frieze in Sgraffito.] A form of external decoration which has been but little used for heraldry, though it is one which is readily adapted to the purpose, is that kind of cement work in layers that is known as Sgraffito. Examples of this method of work are shown in the friezes, Figs. 198 and 199, in which the heraldry adds interest to very graceful design, and in the panel of the Armorials of Pope Paul III (Fig. 200). [Illustration: FIG. 199.--Frieze in Sgraffito.] In Sgraffito work the design is drawn through a coat of moist plaster on to a lower one of another colour, much as etching is drawn through the ground on to the copper, and like it is, in its simplest form, a line art. [Illustration: FIG. 200.--Arms of Pope Paul III (Farnese). Panel in Sgraffito.]