The Boundary Pattern represents the design of the limiting edge of a system. It is one aspect of the more foundational Pattern, Structure. Boundary demonstrates the perimeter frame or border that defines a system and determines what may come into and what may go out of a system. Permeability, which allows the movement of elements into and out of the system, must be balanced with structural integrity, which defines the system through the separation of the elements inside and outside of the system. The role of Boundary is to maintain distinctions.
The principle of edge design: the enduring health of any system depends on the balance and integration of structural definition and well designed permeability of edge structures, for a given context.