graph LR
subgraph one
    A
end
subgraph two
    B
end
A --> B
---
+-------+ +-------+
|  one  | |  two  |
|       | |       |
|       | |       |
| +---+ | | +---+ |
| |   | | | |   | |
| | A |---->| B | |
| |   | | | |   | |
| +---+ | | +---+ |
|       | |       |
+-------+ +-------+
