polygon_test():

  Define polygon vertices V:
[[0 0]
 [4 0]
 [2 2]
 [1 2]
 [0 1]
 [1 1]]

  Plot outline of polygon:
  Graphics saved as "polygon_outline.png"

  Triangulate the polygon:
[[0 1 2]
 [2 3 5]
 [3 4 5]]

  Plot the triangulated polygon:
  Graphics saved as "polygon_filled.png"

  Polygon area by shoelace =  5.0

  Polygon area by triangulation =  4.999999999999998

  Polygon centroid =  [1.8        0.83333333]

  polygon_contains_point()?
  Polygon does NOT contain  [0.0, 0.5]
  Polygon does contain  [0.75, 1.25]
  Polygon does contain  [2.5, 1.0]
  Polygon does NOT contain  [1.5, 2.5]

  Estimate integral of f(x,y) using 1 point triangle rule
21.16666666666666

  Estimate integral of f(x,y) using 6 point triangle rule
24.833333333333314