I am getting those funny lines on my pdf printing of the heuristic net.
It's really noticeable when you blow things up.
As I'm printing on A0 you have to blow it up to read it.
There is an addon in Adobe Pro called Touchup Object Tool that allows you
to remove them one by one.
Seems that there are lots of layers. I will provide a sample if necessary
I'm not quite sure what these funny lines are, but I guess they are the straight gray lines between the nodes in the graph that I used to get. If there was a normal (usually black and curved) arc between two nodes, there would also be a straight gray line between these two nodes. In my case I could solve this by using a different PDF generator (I think I had these problems when using Acrobat, but not when using doPDF).