diff --git a/ADIS_Csharp/ConsoleApp/Program.cs b/ADIS_Csharp/ConsoleApp/Program.cs
index 942b3a2..0f3c322 100644
--- a/ADIS_Csharp/ConsoleApp/Program.cs
+++ b/ADIS_Csharp/ConsoleApp/Program.cs
@@ -132,7 +132,7 @@ class ThreadStop2
 #endif
 
 
-#if true
+#if false
 class SimpleBlocking
 {
 
@@ -167,4 +167,38 @@ class SimpleBlocking
 
 }
 
+#endif
+
+#if true
+
+class LockingConstruct1 {
+    private static object locker = new object();
+
+    static void Main()
+    {
+        long sum = 0;
+
+        Thread t1 = new Thread(delegate()
+        {
+            lock (locker)
+            {
+                for (int i = 0; i <= 1000; i++) {
+                    sum += i;
+                }
+            }
+        });
+
+        Thread t2 = new Thread(delegate()
+        {
+            lock (locker)
+            {
+                Console.WriteLine("Summe = " + sum);
+            }
+        });
+
+        t1.Start();
+        t2.Start();
+    }
+}
+
 #endif
\ No newline at end of file