diff --git a/Circular_kernel_3/TODO b/Circular_kernel_3/TODO
index f0fc4c474cf..ff3820065fe 100644
--- a/Circular_kernel_3/TODO
+++ b/Circular_kernel_3/TODO
@@ -6,6 +6,12 @@ remplacer les std::acos(-1.) par CGAL_PI
 
 cercle par 3 points
 
+============
+
+to think about:
+is there a way move do_intersect(Circle3,Circle3) to Intersection package?
+(no use of sqrt?)
+
 ============
 nettoyer 
 Solve