graph LR
X
subgraph one
    A --> B
end
Y
X --> A
B --> Y
---
        +-----------------+        
        |       one       |        
        |                 |        
        |                 |        
+---+   | +---+     +---+ |   +---+
|   |   | |   |     |   | |   |   |
| X |---->| A |---->| B |---->| Y |
|   |   | |   |     |   | |   |   |
+---+   | +---+     +---+ |   +---+
        |                 |        
        +-----------------+        
