>>> from rene.exact import (Contour,
...                         Empty,
...                         Point,
...                         Polygon)
>>> square = Polygon(Contour([Point(0, 0), Point(4, 0), Point(4, 4),
...                           Point(0, 4)]),
...                  [])
>>> square == square
True
>>> square & square == square
True
>>> square | square == square
True
>>> square - square == Empty()
True
>>> square ^ square == Empty()
True
>>> len(square.border.vertices) == 4
True
>>> len(square.holes) == 0
True
>>> from rene.exact import ConstrainedDelaunayTriangulation
>>> (ConstrainedDelaunayTriangulation.from_polygon(square).triangles
...  == [Contour([Point(0, 0), Point(4, 0), Point(0, 4)]),
...      Contour([Point(0, 4), Point(4, 0), Point(4, 4)])])
True
>>> from rene import Location
>>> from rene.exact import Trapezoidation
>>> trapezoidation = Trapezoidation.from_polygon(square)
>>> all(vertex in trapezoidation for vertex in square.border.vertices)
True
>>> all(trapezoidation.locate(vertex) is Location.BOUNDARY
...     for vertex in square.border.vertices)
True