Deterministic, fractal defect structures in close packings of hard disks

Certain close packings of disks around rhomboidal seeds contain deterministic fractal defect structures. The defects, in the form of stacking faults, grow and bifurcate by deterministic rules. We derive the fractal dimension of the defect structure, a universal function independent of all variables except the acute angle of the rhomboidal seed. © 1986 The American Physical Society.