>>> from poligon import Poligon
>>> p = Poligon()
>>> len(p)
0
>>> from punt2D import Punt2D
>>> p1 = Punt2D(2, 3)
>>> p.afegir_vertex(p1)
>>> len(p)
1
>>> print(p[0])
Punt2D(2, 3)

--fi-enunciat

>>> p2 = Punt2D(5, 3)
>>> p.afegir_vertex(p2)
>>> print(p[1])
Punt2D(5, 3)
>>> p1, p2 = p.obtenir_aresta(0)
>>> print(p1, p2)
Punt2D(2, 3) Punt2D(5, 3)
>>> p3 = Punt2D(4, 7)
>>> p.afegir_vertex(p3)
>>> len(p)
3
>>> p1, p2 = p.obtenir_aresta(2)
>>> print(p1, p2)
Punt2D(4, 7) Punt2D(2, 3)