The same may be said of the pediments. The angle of the low-pitched roof left another interstice for the sculptor at each end of the building; and I have elsewhere[2] pointed out the influence of the inclosing space and the angles of the pediment of the Parthenon upon the arrangement of the groups within it, and even upon the lines taken by some of the figures, especially the reclining figures near the acute angles.
[2] See "Bases of Design."
Certain lines become inseparably associated with constructive expression, and are used to emphasize it, as the vertical flutings of the Doric column, by repeating the lines of the column itself, emphasize its constructive expression of supporting the weight of the horizontal lintels, the lines of which, repeated in the mouldings of the frieze and cornice, are associated with level restfulness and secure repose.
As examples of design which, while meeting the structural necessities and acknowledging the control of space and general conditions, as the form of the slabs upon which they are sculptured, yet expresses independent movement, the figures of the octagonal tower of the winds at Athens are interesting (see illustration, p. [115]).
Quite a different feeling, corresponding to differences in conception and spirit in design, comes in with the Roman round arch its allied forms of spandril and vault, lunette and medallion, presenting new spaces for the surface designer, and new suggestions of ornamental line (see illustration, p. [117]). It is noticeable how, with the round-arched architecture under Roman, Byzantine (see illustration, p. [118]), and Renaissance forms, the scroll form of ornament developed, the reason being, I think, that it gave the necessary element of recurring line, whether used in the horizontal frieze in association with round arches, or in spandrils of vaults and arcades, and on marble mosaic pavements.
Value of the Recurring Line