diff --git a/pmc/include/rectangle.h b/pmc/include/rectangle.h
--- a/pmc/include/rectangle.h
+++ b/pmc/include/rectangle.h
@@ -15,7 +15,7 @@
     Vector * P[4];
 
   public:
-    Rectangle (Surface *, Vector p1, Vector p2, Vector p3, Vector p4);
+    Rectangle (Surface *, Vector& p1, Vector& p2, Vector& p3, Vector& p4);
     Rectangle (Surface *);
     virtual ~ Rectangle ();
     void move (Vector);