There is some work going on in Sage (http://www.sagemath.org) to more
fully use matplotlib on a higher level than is currently done. One
issue that is coming up is using matplotlib to make a plot with axis
lines crossing in the center of the plot, like is shown in the plot at
Is this easy to do in matplotlib (preferably with the stock axes
object)? It seems that there is not an example illustrating an axes of this form and I couldn't find any mention in the documentation of such a feature.