................................................
: v
+----------+ +------+ +----------+ +---------+ +---------+
| 1Bonn | --> | 1Ulm | --> | 1Bautzen | --> | 1Berlin | --> | 1Kassel |
+----------+ +------+ +----------+ +---------+ +---------+
! |
! |
v |
+----------+ |
| 1Koblenz | <-----+
+----------+
................................................
: v
+----------+ +------+ +----------+ +---------+ +---------+
| 2Bonn | --> | 2Ulm | --> | 2Bautzen | --> | 2Berlin | --> | 2Kassel |
+----------+ +------+ +----------+ +---------+ +---------+
! |
! |
v |
+----------+ |
| 2Koblenz | <-----+
+----------+
................................................
: v
+----------+ +------+ +----------+ +---------+ +---------+
| Bonn | --> | Ulm | --> | Bautzen | --> | Berlin | --> | Kassel |
+----------+ +------+ +----------+ +---------+ +---------+
! |
! |
v |
+----------+ |
| Koblenz | <-----+
+----------+