Radiation - Structural
Subdivisions and Unit Forms

In a centrifugal structure, the subdivisions are generally repetitive in both shape and size. Unit forms fit these subdivisions in the same way that they fit those in a repetition structure, except that the subdivisions normally carry the unit forms in their directional rotation. The unit forms may conform to the directions of the subdivisions or maintain a constant angel to the axis of each subdivision.

Within each of the subdivisions in a centrifugal structure, finer subdivisions can be constructed if desired. A sequence of parallel lines can be employed for the purpose, but there is virtually no limit to the ways of making further subdivisions.

In a regular concentric structure, the subdivisions are in the form of a ring which can only accommodate unit forms of a linear nature. A centrifugal structure is usually required for making fine subdivisions, and each ring can be rotated variably, if necessary, so that the subdivisions in one ring do not have to align with those in the next ring. Subdivisions obtained in this way are generally repetitive within each ring, but gradational from the center towards outer rings. Unit forms fit these subdivisions in the same way as they fit those in a gradation structure. Of course it is also possible to subdivide each concentric ring in a different manner if desired.

In a regular centripetal structure, the subdivisions are defined by sets of parallel lines which curl or bend towards the center. These can be further divided by superimposing sets of parallel lines, another centripetal structure, or a concentric structure.