add-line to itself

I'm trying to devise a way to display some neural networks that allow recurrent connections. So far I've been using the "add-line" method between sphere objects to represent connections between nodes, but this doesn't work if there is a recurrent connection from a node into itself. The code "object add-line to object" doesn't get the desired result. I would like to draw some kind of loop exiting the sphere, going around and re-entering it from the other side, or something like that. Any recommendations on an easy way to do that?

Also, in general, is there any way to draw curved lines?

-Jacob