All,

In the code on:

http://matplotlib.sourceforge.net/examples/api/bbox_intersect.html

I think I've figured out that:

vertices = (np.random.random((4, 2))-0.5)*6.0

vertices = np.ma.masked_array(vertices, [[False, False], [True, True], [False, False], [False, False]])

prevents the second of four random vertices from being used. But I'm not sure why

plot(vertices[:, 0], vertices[:, 1], color=color)

seems to connect only two points for a line segment.

Can someone explain?

D.