graph TD
A[Server] --> B[Client]
C[Server] --> D[Client]
---
+--------+     +--------+
|        |     |        |
| Server |     | Server |
|        |     |        |
+--------+     +--------+
     |              |    
     |              |    
     |              |    
     |              |    
     v              v    
+--------+     +--------+
|        |     |        |
| Client |     | Client |
|        |     |        |
+--------+     +--------+