Not sure if there is any utility in this, but I created a (not really) time-lapse video of dot working on a graph.
OK, not really a time-lapse - really 12 individual dot runs with varying values for  nslimit (01  04  16 32) (nslimit | Graphviz) and  mclimit ( 0.1 0.5 1.0) (mclimit | Graphviz) to throttle the work done by the major internal routines.
the home movie: subway.mp4 - Google Drive
I was surprise at how much things changed from one image to the next.  Dot is a hard worker.
Nothing special about this graph, other than colored nodes & edges.  I did not create it.
Don’t forget your popcorn!