This demo illustrates how to:

* Generate a 2D mesh of a polygon
* Generate a 3D mesh of a polyhedral using .off files


Problem definition
------------------

This demo focuses purely on generating meshes. In this demo we will
use the following classes in DOLFIN:

* :py:class:`PolygonalMeshGenerator <dolfin.cpp.mesh.PolygonalMeshGenerator>`
* :py:class:`PolyhedralMeshGenerator <dolfin.cpp.mesh.PolyhedralMeshGenerator>`
