There are also these funky heaping patterns to figure out. These are harmonic
(not sub-harmonic) patterns formed using 0.25 mm.
glass beads shaken at high
amplitude (~1 cm.) in the presence of air. Snapshots
are taken ~15 sec. apart.
See related work by Bob
Behringer as well.
Correspondingly, here are results from an equally funky model. These are
snapshots
taken 25 timesteps apart. The horizontal size of the
patterns in both experiment and
simulation scales like Time-1/3.
Shinbrot, T., "Granular Coarsening," Granular Matter 1 (1998), 145-8