+---+
| E |
+---+
^
|
|
|
| +---+
+----+-> | B |
| +---+
|
|
|
| +---+
+-> | C |
| +---+
|
|
|
| +---+
+-> | D |
+---+
+---+
| E |
+---+
^
|
|
|
| +---+
+----+-> | B |
| +---+
|
|
|
| +---+
+-> | C |
| +---+
|
|
|
| +---+
+-> | D |
+---+