Hamiltonian mappings and circle packing phase spaces
  We introduce three area preserving maps with phase space structures which resemble circle packings. Each mapping is derived from a kicked Hamiltonian system with one of three different phase space geometries (planar, hyperbolic or spherical) and exhibits an infinite number of coexisting stable periodic orbits which appear to `pack' the phase space with circular resonances. 
A.J.Scott, C.A.Holmes and G.J.Milburn