Fig. 2.

A possible geometrical construction (hybrid Huygens–Descartes) for a channel between two dopants. For more dopants, these diamonds could be strung together, but because they represent only a first-order approximation to a self-organized pattern, simple curvilinear channel coordinates z,ρ centered on dopant chain segments would probably be an equally or even more effective partitioning. In principle, both constructions can be examined experimentally.