  Recent experiments have shown that many species of microorganisms leave a
solid surface at a fixed angle determined by steric interactions and near-field
hydrodynamics. This angle is completely independent of the incoming angle. For
several collisions in a closed body this determines a unique type of billiard
system, an aspecular billiard in which the outgoing angle is fixed for all
collisions. We analyze such a system using numerical simulation of this
billiard for varying tables and outgoing angles, and also utilize the theory of
one-dimensional maps and wavefront dynamics. When applicable we cite results
from and compare our system to similar billiard systems in the literature. We
focus on examples from three broad classes: the ellipse, the Bunimovich
billiards, and the Sinai billiards. The effect of a noisy outgoing angle is
also discussed.
