Rule 4c. The appendage should, if possible, echo or repeat some lines similar in character and direction to those of the primary mass.
Outline or Contour Enrichment
Rule 5a. Outline enrichment should be subordinated to and support the structure.
Rule 5b. Outline enrichment should add grace, lightness, and variety to the design.
Rule 5c. Outline enrichment, by its similarity, should give a sense of oneness or unity to the design, binding divergent members together.
Rule 5d. Parts of one design differing in function should differ in appearance but be co-ordinated with the entire design.
Rule 5e. In cylindrical forms outline curves with a vertical tendency should have their turning points or units of measurement in accordance with the horizontal divisions of Rules 2a and 2b.
Rule 5f. Dependent outline enrichment should be related to essential parts of a design and influenced by their forms and functions; it must be consistent with the idea of the subject.
Rule 5g. A curve should join a straight line with either a tangential or right angle junction.