M. Blanc[82] says of the general laws of ornamentation: "There can be
no nobler satisfaction to the mind, than to be able to unravel what is
beyond measure complicated, to diminish what is apparently immense,
and to reduce to a few clear points what has been till now involved in
a haze of obscurity. Just as the twenty-six letters of the alphabet
have been, and always will be sufficient to form the expression of the
words necessary for all human thought, so certain elements susceptible
of combination among themselves have sufficed, and will suffice, to
create ornament, whose variety may be indefinitely multiplied."

He reduces ornamental design to five principles, Repetition,
Alternation, Symmetry, Progression, and Confusion.

[Illustration: Fig. 5.
Wave Pattern.]

First, Repetition. "You may act on the mind, through sight, by the
same means as those that will excite physical sensations. A single
prick of a pin is nothing, but a hundred such will be intolerably
painful. Repetition produces pleasurable sensations, as well as
painful ones." An insignificant form can become interesting by
repetition, and by the suggestion which, singly, it could not
originate. For example, the rolling of the Greek scroll or wave
pattern awakens in us the idea of one object following another. "It
also suggests the waves of the ocean; or the poet may see in it a
troop of maidens pursuing each other in space, not frivolously, but in
cadence, as if executing a mystic dance." Change the curves into
angular forms, as making the key pattern, and it will no longer flow,
but become as severe as the other was graceful. No principle gives
greater pleasure than repetition, and next to it, _alternation_.

[Illustration: Fig. 6.
Key Pattern.]

Variety is here added to the law of repetition. "There can be
repetition without alternation, but no alternation without
repetition." Alternation is, then, a succession of two objects
recurring regularly in turn; and the cadence of appearance and
disappearance gives pleasure to the senses, whether it be addressed to
taste, hearing, or sight. Alternate rhymes, and even short and long
lines, soothe the ear in verse. In form, the alternations are the more
agreeable, the more they differ. Such are, in architecture, a
succession of metopes and triglyphs on a Doric frieze, where the
circle and the straight lines relieve each other.

[Illustration: Fig. 7.
Metopes and Triglyphs.]

Symmetry. T