diff --git a/.obsidian/workspace.json b/.obsidian/workspace.json
index 066abd6..c5dd9da 100644
--- a/.obsidian/workspace.json
+++ b/.obsidian/workspace.json
@@ -35,8 +35,7 @@
               "title": "4 - Semaphores"
             }
           }
-        ],
-        "currentTab": 1
+        ]
       }
     ],
     "direction": "vertical"
@@ -205,10 +204,10 @@
       "companion:Toggle completion": false
     }
   },
-  "active": "e453bba00fdc57d6",
+  "active": "7c5b0ca6f7687800",
   "lastOpenFiles": [
-    "Concurrent Systems/test/Untitled.md",
     "Concurrent Systems/notes/4 - Semaphores.md",
+    "Concurrent Systems/test/Untitled.md",
     "Concurrent Systems/notes/4b - Monitors.md",
     "Concurrent Systems/notes/4c - Dining Philosophers.md",
     "Concurrent Systems/notes/5 - Software Transactional Memory.md",
diff --git a/Concurrent Systems/test/Untitled.md b/Concurrent Systems/test/Untitled.md
index 54ec6ba..72d21aa 100644
--- a/Concurrent Systems/test/Untitled.md	
+++ b/Concurrent Systems/test/Untitled.md	
@@ -6,7 +6,9 @@ begin_read() :=
 	PR_MUTEX.down()
 	R_MUTEX.down()
 	R++ # currently active readers
-	if R = 1 then GLOB_MUTEX.down()
+	if R = 1 then
+		W_MUTEX.down()
+		GLOB_MUTEX.down()
 	R_MUTEX.up()
 	PR_MUTEX.up()
 	return
@@ -19,11 +21,14 @@ end_read() :=
 	return
 
 begin_write() :=
+	W_MUTEX.down()
+	W_MUTEX.up()
 	PR_MUTEX.down()
 	GLOB_MUTEX.down()
 	return
 
 end_write() :=
+	PR_MUTEX.up()
 	GLOB_MUTEX.up()
 	return
 ```
\ No newline at end of file