graph LR
A
B
B --> A
A --> A
B --> C
C --> A
---
+---+     +---+
|   |     |   |
| A |<-+--| C |
|   |  |  |   |
+---+  |  +---+
  ^    |    ^  
  |    |    |  
  +----+    |  
  |         |  
  |         |  
+---+       |  
|   |       |  
| B |-------+  
|   |          
+---+          
