  In this paper, we consider the dynamics of a heavy homogeneous ball moving
under the influence of dry friction on a fixed horizontal plane. We assume the
ball to slide without rolling. We demonstrate that the plane may be divided
into two regions, each characterized by a distinct coefficient of friction, so
that balls with equal initial linear and angular velocity will converge upon
the same point from different initial locations along a certain segment. We
construct the boundary between the two regions explicitly and discuss possible
applications to real physical systems.
