Anyone completed the exercise?

I think the point is just that standard tools like to avoid nodes overlapping each other, so if you have a million nodes on screen then each node must occupy only about 1 pixel, and you wouldn't be able to get any information about the problem other than “a million sure is a big number, isn't it?”. But it wasn't really a serious suggestion for understanding the bug, which could be illustrated with just one or two child processes.

(I was hoping to be able to point people to a certain impressive tool I've seen for interactively exploring large graphs, but I see that the code isn't yet publicly available. However, it's expected to be redeveloped and GPL'd in a year or two, under the name Dunnart.)