diff --git a/birdie.py b/birdie.py
index e615e96..4128fd4 100644
--- a/birdie.py
+++ b/birdie.py
@@ -10,6 +10,8 @@ def on_mouse_down():
 
 def update():
     titi.x += titi.speed
+    tube_sup.x -= vitesse_defilement
+    tube_inf.x -= vitesse_defilement
 
 def draw():
     screen.blit('background', (0, 0))
@@ -25,4 +27,7 @@ ecart = 140
 tube_sup = Actor ('top',(300,0))
 tube_inf = Actor ('bottom',(300,tube_sup.height + ecart))
 
+vitesse_defilement =1
+
+
 pgzrun.go()