A train leaves the station (bottom) heading west. Can it return to the station heading east?
Is there anywhere the train might get stuck?
Is there anywhere the train can reach but only from one direction?
I call this directed node networks. As the arcs are bidirectional, but the nodes have an A and B side with a parity requirement.
Inspired by the frustrating traps of Penrose's Railway Mazes.
Edit: just for reference, I have an MMath specialising in fluid dynamics - so I am well grounded in the basics of graph theory and have done intro to topology, so whilst this in not in my typical wheelhouses, I am looking for a more specific research area.
