diff --git a/dm4/bin/dune b/dm4/bin/dune
index 1f3ac32..f606d05 100644
--- a/dm4/bin/dune
+++ b/dm4/bin/dune
@@ -1,4 +1,4 @@
 (executable
  (public_name dm4)
  (name main)
- (libraries dm4))
+ (libraries dm4))
\ No newline at end of file
diff --git a/dm4/bin/main.ml b/dm4/bin/main.ml
index 2860d26..78e0a8f 100644
--- a/dm4/bin/main.ml
+++ b/dm4/bin/main.ml
@@ -1,4 +1,28 @@
+(* let plusetfois a b = (a+b, a*b);;
+(* assert (plusetfois 5 6 == (11, 30));; *)
 
-let plusetfois a b = (a+b, a*b);;
+let rec pp2_h n = match n with
+  | 0 -> 1
+  | _ -> 2 * (pp2_h (n/2))
+;;
+let pp2 n = if n == 0 then 0 else pp2_h (n-1);;
 
-assert (plusetfois 5 6 == (11, 30));;
+(* assert (pp2 10 == 16);;
+assert (pp2 32 == 32);;
+assert (pp2 1 == 1);;
+assert (pp2 0 == 0);; *)
+
+let leeloo l = match l with
+  | _::_::_::_::a::_ -> a
+  | _ -> failwith "Not enough elements";;
+
+(* assert (leeloo [2; 65; 2; 3; 7; 2] == 7);; *)
+
+let rec coupe l = match l with
+  | a::b::q ->
+    let qa, qb = coupe q in
+    a::qa, b::qb
+  | _ -> l, []
+;;
+
+(* assert (coupe [2; 65; 4; 3; 7; 2] == ([2; 4; 7], [65; 3; 2])); *) *)
\ No newline at end of file
diff --git a/dm4/lib/dune b/dm4/lib/dune
index 485ff58..3247f9b 100644
--- a/dm4/lib/dune
+++ b/dm4/lib/dune
@@ -1,2 +1,3 @@
 (library
- (name dm4))
+ (name lib)
+ (public_name dm4))
diff --git a/dm4/lib/lib.ml b/dm4/lib/lib.ml
new file mode 100644
index 0000000..aff1634
--- /dev/null
+++ b/dm4/lib/lib.ml
@@ -0,0 +1,46 @@
+let plusetfois a b = (a+b, a*b);;
+
+let rec pp2_h n = match n with
+  | 0 -> 1
+  | _ -> 2 * (pp2_h (n/2))
+
+let pp2 n = if n == 0 then 0 else pp2_h (n-1)
+
+let leeloo l = match l with
+  | _::_::_::_::a::_ -> a
+  | _ -> failwith "Not enough elements"
+
+let rec coupe l = match l with
+  | a::b::q ->
+    let qa, qb = coupe q in
+    a::qa, b::qb
+  | _ -> l, []
+
+let rec colle la lb = match la with
+  | [] -> lb
+  | a::q -> a::(colle lb q)
+
+let rec compte l x = match l with
+  | [] -> 0
+  | a::q -> if a == x then 1+(compte q x) else compte q x
+
+let rec sommesi l f = match l with
+  | [] -> 0
+  | a::q -> if f a then a+(sommesi q f) else (sommesi q f)
+
+let rec majopred_h l f acc acc_n = match l with
+  | [] -> 2*acc >= acc_n
+  | a::q -> majopred_h q f (if f a then acc+1 else acc) (acc_n+1)
+let majopred l f = majopred_h l f 0 0
+
+let rec lexico la lb = match la, lb with
+  | [], _ -> true
+  | _, [] -> false
+  | a::_, b::_ when a < b -> true
+  | a::_, b::_ when a > b -> false
+  | _::qa, _::qb -> lexico qa qb
+
+let rec aplatir l = match l with
+  | [] -> []
+  | []::ql -> aplatir ql
+  | (a::q)::ql -> a::(aplatir (q::ql))
\ No newline at end of file
diff --git a/dm4/test/dune b/dm4/test/dune
index 49f0800..b0b4a2f 100644
--- a/dm4/test/dune
+++ b/dm4/test/dune
@@ -1,2 +1,3 @@
-(test
- (name test_dm4))
+(executable
+ (name test_dm4)
+ (libraries lib))
diff --git a/dm4/test/test_dm4.ml b/dm4/test/test_dm4.ml
index e69de29..35c13ef 100644
--- a/dm4/test/test_dm4.ml
+++ b/dm4/test/test_dm4.ml
@@ -0,0 +1,35 @@
+open Lib;;
+
+assert (plusetfois 5 6 = (11, 30));;
+
+assert (pp2 10 = 16);;
+assert (pp2 32 = 32);;
+assert (pp2 1 = 1);;
+assert (pp2 0 = 0);;
+
+assert (leeloo [2; 65; 2; 3; 7; 2] = 7);;
+
+assert (coupe [2; 65; 4; 3; 7; 2] = ([2; 4; 7], [65; 3; 2]));;
+assert (coupe [2; 65; 4; 3; 7; 2; 0] = ([2; 4; 7; 0], [65; 3; 2]));;
+
+assert (colle [2; 4; 7] [65; 3; 2] = [2; 65; 4; 3; 7; 2]);;
+assert (colle [2; 4; 7; 0] [65; 3; 2] = [2; 65; 4; 3; 7; 2; 0]);;
+
+assert (compte [2; 65; 4; 3; 7; 2] 2 = 2);;
+
+assert (sommesi [2; 65; 4; 3; 7; 2] (fun x -> x mod 2 = 1) = 75);;
+
+assert (majopred [2; 65; 4; 3; 7; 2] (fun x -> x mod 2 = 1));;
+assert (not (majopred [2; 65; 6; 4; 3; 7; 2] (fun x -> x mod 2 = 1)));;
+
+assert (lexico [2; 4; 7] [2; 4; 7]);;
+assert (not (lexico [2; 4; 7; 3] [2; 4; 7]));;
+assert (lexico [2; 4; 7] [2; 4; 7; 3]);;
+assert (lexico [2; 4; 7] [2; 5; 7]);;
+assert (not(lexico [2; 5; 7] [2; 4; 7]));;
+
+assert (aplatir [[1; 2]; [3; 4]] = [1; 2; 3; 4]);;
+assert (aplatir [[]; [3; 4]] = [3; 4]);;
+assert (aplatir [] = []);;
+assert (aplatir [[]] = []);;
+assert (aplatir [[]; []] = []);;
\ No newline at end of file