# different chains of nodes
[ Ulm ] -> [ Lahn ] -> [ Bonn ]
-> [ Trier ]
[ Stein ] -> [ Wahns ]
-> [ Lind ]
-> [ Burg ] -> [ Buch ]
# different chains of nodes
[ Ulm ] -> [ Lahn ] -> [ Bonn ]
-> [ Trier ]
[ Stein ] -> [ Wahns ]
-> [ Lind ]
-> [ Burg ] -> [ Buch ]