diff --git a/6design/design.md b/6design/design.md
index fcf8c91..07a4e72 100644
--- a/6design/design.md
+++ b/6design/design.md
@@ -45,11 +45,11 @@ flowchart LR
     proc_cron[Task planner] --> proc_queue
     proc_queue_worker --> ext_bank[(Bank API)]
     proc_queue_worker --> db
-    client[Client/UI] --> api[API Gateway / Web Server]
-    api --> svc[Web API]
+    client[Client/UI] <--> api[API Gateway / Web Server]
+    api <--> svc[Web API]
     svc --> proc_queue
-    svc --> db[(Database)]
-    svc --> cache[(Cache)]
+    svc <--> db[(Database)]
+    svc <--> cache[(Cache)]
 ```
 
 - Components and responsibilities: What does each box do?