Regions, of the kind represented by the ennead, co-exist within complex totalities such as a community of people. When such regions interact in such a way that the significance of each is enhanced, we have the situation of integrative complementarity. This decad can also be understood as a synthesis of two pentads, meaning the synthesis of two independent modes of significance into a total meaning. This system is of value in grappling with problems of the complex and ambiguous modes of significance of man. When we take into account an active co-operation between coupled but independent entities, then we have the condition of a synergism. The eleven-term system applies wherever there is a mutual completion between structures of different kinds.