graph LR
subgraph frontend [Frontend Services]
    A --> B
end
---
+-----------------+
|Frontend Services|
|                 |
|                 |
| +---+     +---+ |
| |   |     |   | |
| | A |---->| B | |
| |   |     |   | |
| +---+     +---+ |
|                 |
+-----------------+
