+---+ +---+ +---+
| A | --> | B | --> | C |
+---+ +---+ +---+
|
+-------------------+
v
+---+ +---+
| D | --> | E |
+---+ +---+
|
+---------+
v
+---+
| F |
+---+
+---+ +---+ +---+
| A | --> | B | --> | C |
+---+ +---+ +---+
|
+-------------------+
v
+---+ +---+
| D | --> | E |
+---+ +---+
|
+---------+
v
+---+
| F |
+---+