+---+
| E |
+---+
|
|
|
|
| +---+
+----+-- | B |
| +---+
|
|
|
| +---+
+-- | C |
| +---+
|
|
|
| +---+
+-- | D |
+---+
+---+
| E |
+---+
|
|
|
|
| +---+
+----+-- | B |
| +---+
|
|
|
| +---+
+-- | C |
| +---+
|
|
|
| +---+
+-- | D |
+---+