car
  +-----------------------------------+
  |                                   v
+------+  train   +--------+  bus   +---------+
| Bonn | =======> | Berlin | .....> | Potsdam |
+------+          +--------+        +---------+
                    !
                    ! bike
                    v
                  +--------+
                  |  Ulm   |
                  +--------+