diff --git a/Algo/Courses/Chapter 6 - Lists (Exercises).md b/Algo/Courses/Chapter 6 - Lists (Exercises).md
index 148dc45..0126433 100644
--- a/Algo/Courses/Chapter 6 - Lists (Exercises).md	
+++ b/Algo/Courses/Chapter 6 - Lists (Exercises).md	
@@ -110,14 +110,14 @@ let maximum = function
 ```
 
 ## Exercise 2.1
+```Ocaml
+let rec arithmetic_list n a1 r =
+  if n <= 0 then []
+  else a1 :: arithmetic_list (n - 1) (a1 + r) r;;
 ```
-let arith_list n a r = 
-	if n < 0 then
-		invalid_arg "n must be superior to 0"
-	else if n = 0 then
-		[]
-	if n = 1 then
-		a::[]
-	else let rec arl =
-		|  
 
+## Exercise 2.2
+```Ocaml
+let concatenate_lists lst1 lst2 =
+  lst1 @ lst2;;
+```