Differences of feeling in arched forms depend upon the relative height of arches and supporting piers and columns. The vertical effect is strongly emphasized when the latter are relatively high, while the effect of weight is increased in flattened arches, which for this reason are especially appropriate for crypts and prison entrances. Interesting complications are introduced in arcades or intersecting vaults, where a single column serves as a support for two or more arches; for there the vertical force is divided, flowing in different directions in the little triangular piece of wall between, or along the ribs of the vaults. Something similar occurs in the Byzantine dome on pendentives, only instead of supporting the horizontal weight of a gallery or a vault, the triangular pendentives meet the outward thrust of a superposed dome. In Renaissance architecture and the modern classical revivals, where Greek and Roman styles are freely adapted to novel modes of life and purpose, no essentially new form was added to architectural speech. There were combinations of old forms into more complex structures, but no new important elements. The most outstanding novelty is perhaps the reversed relation between the whole and the parts. [Footnote: See P. Frankl, _Die Entwicklungsphasen der neueren Baukunst_, 1914.] In the classic styles, whether arched or Greek, the whole is built up of the parts additively; each is a relatively independent center of energy complete in itself; first the columns, then the architrave, frieze, and cornice, then the pediment; or first one row of arches, then another row on top of this, and so on. Coordination is the governing principle. But in the modern adaptations, even where coordination rather than subordination rules in the pictorial sphere, the whole is first dynamically and the parts are secondary. In the typical Renaissance facade, for example, the arches of the windows are rather openings in the walls than supporting members. They are centers of little eddies of force, rather than independent parts of the main determining stream of energy. The wall rises as a whole to its heavy overhanging cornice, despite the horizontal divisions marking the stories. There are, however, important differences between the various modern types; the earlier Renaissance forms, for example, keeping closer to the antique than the later Baroque and Rococo.