diff --git a/.obsidian/workspace.json b/.obsidian/workspace.json
index 461e886..c06623d 100644
--- a/.obsidian/workspace.json
+++ b/.obsidian/workspace.json
@@ -13,7 +13,7 @@
             "state": {
               "type": "markdown",
               "state": {
-                "file": "Algo/Séminaire/Exercices seminaire.md",
+                "file": "Algo/Séminaire/Chapter 4 - A bit of imperative.md",
                 "mode": "source",
                 "source": false
               }
@@ -85,7 +85,7 @@
             "state": {
               "type": "backlink",
               "state": {
-                "file": "Algo/Séminaire/Exercices seminaire.md",
+                "file": "Algo/Séminaire/Chapter 4 - A bit of imperative.md",
                 "collapseAll": false,
                 "extraContext": false,
                 "sortOrder": "alphabetical",
@@ -102,7 +102,7 @@
             "state": {
               "type": "outgoing-link",
               "state": {
-                "file": "Algo/Séminaire/Exercices seminaire.md",
+                "file": "Algo/Séminaire/Chapter 4 - A bit of imperative.md",
                 "linksCollapsed": false,
                 "unlinkedCollapsed": true
               }
@@ -125,7 +125,7 @@
             "state": {
               "type": "outline",
               "state": {
-                "file": "Algo/Séminaire/Exercices seminaire.md"
+                "file": "Algo/Séminaire/Chapter 4 - A bit of imperative.md"
               }
             }
           },
@@ -158,9 +158,10 @@
   },
   "active": "9e7be1904dfd4451",
   "lastOpenFiles": [
+    "Algo/Séminaire/assets/unitaire-meme.png",
     "Algo/Séminaire/Chapter 5 - Recursivity.md",
-    "Algo/Séminaire/Chapter 4 - A bit of imperative.md",
     "Algo/Séminaire/Exercices seminaire.md",
+    "Algo/Séminaire/Chapter 4 - A bit of imperative.md",
     "Algo/Séminaire/Chapter 3 - Case analysis.md",
     "Algo/Séminaire/Introduction.md",
     "Algo/Séminaire/Chapter 2 - Functions.md",
diff --git a/Algo/Séminaire/.DS_Store b/Algo/Séminaire/.DS_Store
new file mode 100644
index 0000000..84f5661
Binary files /dev/null and b/Algo/Séminaire/.DS_Store differ
diff --git a/Algo/Séminaire/Chapter 5 - Recursivity.md b/Algo/Séminaire/Chapter 5 - Recursivity.md
index 284e9e7..3a57428 100644
--- a/Algo/Séminaire/Chapter 5 - Recursivity.md	
+++ b/Algo/Séminaire/Chapter 5 - Recursivity.md	
@@ -61,4 +61,6 @@ flowchart LR
 
 A[ctd 3] --> B[ctd 2] --> C[ctd 1] --> D[ctd 0] --> E[ctd -1] --> F[ ] --> E --> D --> C --> B --> A
 ```
-> ctd is countdown
\ No newline at end of file
+> ctd is countdown
+
+## 5.3. Several recursive calls
diff --git a/Algo/Séminaire/Exercices seminaire.md b/Algo/Séminaire/Exercices seminaire.md
index dea204e..35ba844 100644
--- a/Algo/Séminaire/Exercices seminaire.md	
+++ b/Algo/Séminaire/Exercices seminaire.md	
@@ -269,6 +269,14 @@ A[seq 3] --> B[4*seq2-1] --> C[4*seq1-1] --> D[4*seq0-1] --> E[1] --> F[4*1-1] -
 	| 0 -> u0
 	|n -> q*geo(n-1) in geo n;;
 ```
+## Exercise 4.4
+```Ocaml
+# let rec gcd a b = 
+	if a mod b = 0 then
+		b
+	else
+		gcd b (a mod b);;
+```
 ## Exercise 4.5
 ```Ocaml
 let rec add a = function
diff --git a/Algo/Séminaire/assets/unitaire-meme.png b/Algo/Séminaire/assets/unitaire-meme.png
new file mode 100644
index 0000000..02be7e2
Binary files /dev/null and b/Algo/Séminaire/assets/unitaire-meme.png differ