Delaunay Triangulation and Dirichlet (Voronoi) Tessellation
Calculates the Delaunay triangulation and the Dirichlet
or Voronoi tessellation (with respect to the entire plane) of
a planar point set. Plots triangulations and tessellations in
various ways. Clips tessellations to sub-windows. Calculates
perimeters of tessellations. Summarises information about
the tiles of the tessellation. Calculates the centroidal
Voronoi (Dirichlet) tessellation using Lloyd's algorithm.