Added comments in example proxy also added link to go play sandbox

structural/proxy.md

@@ -8,37 +8,37 @@ The proxy could interface to anything: a network connection, a large object in m
 
 Short idea of implementation:
 ```go
+    // To use proxy and to object they must implement same methods
     type IObject interface {
         ObjDo(action string)
     }
 
+    // Object represents real objects which proxy will delegate data
     type Object struct {
         action string
     }
 
+    // ObjDo implements IObject interface and handels all logic
     func (obj *Object) ObjDo(action string) {
-        // Action handler
+        // Action behaiver
         fmt.Printf("I can, %s", action)
     }
 
+    // ProxyObject represents proxy object with intercepts actions
     type ProxyObject struct {
         object *Object
     }
 
+    // ObjDo are implemented IObject and intercept action before send in real Object
     func (p *ProxyObject) ObjDo(action string) {
         if p.object == nil {
             p.object = new(Object)
         }
         if action == "Run" {
-            p.object.ObjDo(action)
+            p.object.ObjDo(action) // Prints: I can, Run
         }
     }
-
-    func main() {
-        newObj := new(ProxyObject)
-        newObj.ObjDo("Run") // Prints: I can, Run
-    }
 ```
 
 ## Usage
-For usage, see [proxy/main.go](proxy/main.go) or [view in the Playground]().
+For more complex usage, see [proxy/main.go](proxy/main.go) or [view in the Playground](https://play.golang.org/p/VswGMpz-gp).