es, and sundry simple combinations, gradual
development led finally to the delicate forms of Moorish design. The
elaboration of this style involves deep mathematical problems and
careful draftsmanship.

The majority of geometrical ornaments may be divided into three groups.
As we find them in typographical material these groups are bands or
borders, made up visually of repeated units or spots; enclosed spaces or
panels; and unlimited flat patterns or "all-over" designs.

[Illustration: Fig. 27. The development of a motif (stems, leaves, and
berries) into a decorative spot. Diagram in the upper corner shows the
geometrical arrangement of the material. The spot has been repeated to
form a band.]

[Illustration: Fig. 28. Development of the motif used in Fig. 27 into a
natural ornament. The forms and growth are not distorted but the
rendering is in flat surfaces to hold the decorative quality.]

In nearly every style and period of design the plant-world has been the
biggest source of material for adaptation. The direct imitation of
natural forms, keeping as much as possible of their shape, color,
formation, etc., is called naturalistic design. A departure from the
exact details of the natural form, forming the design according to the
rules of rhythm and symmetry, with strict attention to regularity leads
to a result more artificial in character.

Whether the ornament you consider be naturalistic or artificial, the
original source, which is the plant-form or other natural form from
which the design was made, is called the _motif_ of the design. It is
interesting to survey the world about you and note here and there a
recognizable motif in the design of wallpaper, hangings, furniture,
rugs, books, and so on all through the works of man.

The development of a motif into ornament or decoration calls for the use
of all the principles thus far established, plus familiarity with the
medium to be used and the inventiveness that comes only with some
experience. If the reader lacks this experience and is interested in
undertaking to devise ornament or decoration with pen, pencil, or brush,
he is advised to consult some one or more of the books on the subject
which are listed in the bibliography. If he has facility with his pencil
and enthusiasm for the work he will find it a most fascinating
undertaking.

[Illustration: Fig. 29. Initial letter decorated with natural ornament
and a pen sketch treating the motif in a more