sub-graphs for the route via the tunnel and the route for the tunnel's
destination are shown to the right and left respectively. The red line shows the
relationship form by stacking the two sub-graphs. The adjacency on the tunnel
sub-graphs for the route via the tunnel and the route for the tunnel's
destination are shown to the right and left respectively. The red line shows the
relationship form by stacking the two sub-graphs. The adjacency on the tunnel