graph LR
X
subgraph outer
    A
    subgraph inner
        B --> C
    end
    A --> B
end
X --> A
C --> Y
Y
---
        +-----------------------------+      
        |            outer            |      
        |                             |      
        |                             |      
        |         +-----------------+ |      
        |         |      inner      | |      
        |         |                 | |      
        |         |                 | |      
+---+   | +---+   | +---+     +---+ | | +---+
|   |   | |   |   | |   |     |   | | | |   |
| X |---->| A |---->| B |---->| C |---->| Y |
|   |   | |   |   | |   |     |   | | | |   |
+---+   | +---+   | +---+     +---+ | | +---+
        |         |                 | |      
        |         +-----------------+ |      
        |                             |      
        +-----------------------------+      
