There can be no partial systems. Systems can be divided multiplyingly only into whole systems. There is a cosmic hierarchy of primitively symmetric systemic states of intertransformability or interassociabilities of prime polyhedra. People think of a point as the most primitive thing with which to initiate geometrical conceptioning. Points always amplify optically to be identifiable as systemic polyhedra.
All conceptual consideration is inherently four-dimensional.
Thus the primitive is a priori four-dimensional, being always comprised of the four planes of reference of the tetrahedron. There can never be any less than four primitive dimensions.