The Axis Mundi in its various forms illustrates the idea, as do the cross of Jesus crucifixion, the poles of the Sundance, and many others. Both axes and openings have obvious parallels in the human body, as well as in many micro and macro dimensions. Not surprisingly, people have given them male and female tones. The center is marked by an axis together with an opening, linking the above, the below, and the here, and forming a pathway for communication with all the realms. Together axes and openings mark the center of being, that is everywhere at once, much as every raisin in the bread is the center from which the dough expands when rising.
Boundaries function as corridors.
Natural boundaries, referred to as edges on a smaller scale, and as ecotones on a larger scale, are rich, complex phenomena that stimulate symbolic improvisation. Edges are illustrated by the joining of a meadow with a wood, or by shorelines of lakes, ponds, and streams. Ecotones are zones of overlap between two major life zones such as the meeting of the High Plains and the Rocky Mountains. The result is a mixture of the life from each, and often the ecotone is more diverse, complex, and rich than either life zone alone. Culturally-designated sacred places are often ecotones.