>>> import punt2D_plus
>>> import punt2D
>>> p = punt2D_plus.Punt2D_plus(3, 4, (23, 45, 67), 0.1)
>>> isinstance(p, punt2D.Punt2D)
True
>>> isinstance(p, punt2D_plus.Punt2D_plus)
True
>>> p.x
3
>>> p.y
4
>>> p.col
(23, 45, 67)
>>> p.diam
0.1
>>> r = punt2D.Punt2D()
>>> p.dist(r)
5.0