diff --git a/README.MD b/README.MD
index 7eb4501..bccfe45 100644
--- a/README.MD
+++ b/README.MD
@@ -26,24 +26,11 @@ Just for learn.
 - [x] Friendly PoC Interface
 - [x] Web GUI(using WebSocket)
 
-## Extension
-
-You only need to implement these interfaces when extending function or poc.
-
-```go
-type Gatherer interface {
-    // Set params.
-    Set(...interface{})
-    // Run your function.
-    Run()
-    // Report your result.
-    Report() map[string]interface{}
-}
-```
+## Design Pattern
 
-It's almost same for Attacker and PoC.
+I choose **Composite Pattern** to extend function and poc easily.
 
-But I think PoC should also implement `Info() string` interface to return a short brief of the vulnerability.
+![](./design-pattern.png)
 
 ## Installation
 
diff --git a/design-pattern.png b/design-pattern.png
new file mode 100644
index 0000000..9b0572c
Binary files /dev/null and b/design-pattern.png differ