Boxes and relationships

The entities are linked with named n:m relationships and I'd

    > like to select one and display it in a box (with the entity
    > name) and all related entities likewise in boxes linked to
    > each other by lines representing the relationships tagged
    > with the names of those relationships.

matplotlib may not be the best choice (someone already pointed you to
graphviz and pydot). See also pyx.

But there is a graph drawing module for matplotlib -- see