diff --git a/Linear_cell_complex/demo/Linear_cell_complex/Viewer.cpp b/Linear_cell_complex/demo/Linear_cell_complex/Viewer.cpp
index 6187787bc19..75ce3dce7c2 100644
--- a/Linear_cell_complex/demo/Linear_cell_complex/Viewer.cpp
+++ b/Linear_cell_complex/demo/Linear_cell_complex/Viewer.cpp
@@ -16,17 +16,16 @@
 #include <CGAL/Qt/vec.h>
 
 Viewer::Viewer(QWidget *parent)
-    // TODO: add a new constructor that does not take graphic buffer.
-    : Base(parent, ""), m_drawing_functor(MyDrawingFunctorLCC()),
-      m_nofaces(false), m_random_face_color(false),
+    : Base(parent, ""), m_drawing_functor_(MyDrawingFunctorLCC()),
+      m_nofaces_(false), m_random_face_color_(false),
       m_previous_scene_empty(true) {}
 
 void Viewer::setScene(Scene *scene_, bool doredraw) {
   scene = scene_;
 
   if (scene->lcc != nullptr) {
-    compute_elements(gBuffer, scene->lcc, m_drawing_functor, m_nofaces,
-                     m_random_face_color);
+    CGAL::add_in_graphic_buffer_lcc(gBuffer, m_drawing_functor_, scene->lcc, m_nofaces_,
+                              m_random_face_color_);
   }
 
   if (doredraw) {
@@ -35,8 +34,9 @@ void Viewer::setScene(Scene *scene_, bool doredraw) {
 }
 
 void Viewer::sceneChanged() {
-  compute_elements(gBuffer, scene->lcc, m_drawing_functor, m_nofaces,
-                   m_random_face_color);
+
+  CGAL::add_in_graphic_buffer_lcc(gBuffer, m_drawing_functor_, scene->lcc,
+                                  m_nofaces_, m_random_face_color_);
 
   this->camera()->setSceneBoundingBox(
       CGAL::qglviewer::Vec(gBuffer.get_bounding_box().xmin(),
diff --git a/Linear_cell_complex/demo/Linear_cell_complex/Viewer.h b/Linear_cell_complex/demo/Linear_cell_complex/Viewer.h
index f25f73de78a..cd86e153083 100644
--- a/Linear_cell_complex/demo/Linear_cell_complex/Viewer.h
+++ b/Linear_cell_complex/demo/Linear_cell_complex/Viewer.h
@@ -16,7 +16,10 @@
 
 #include "typedefs.h"
 
-#include <CGAL/draw_linear_cell_complex_function.h>
+// QUESTION: When I added this line compiler tell me "No such file or directory!" how?
+// #include <CGAL/draw_linear_cell_complex_function.h>
+
+#include <CGAL/draw_linear_cell_complex.h>
 #include <CGAL/Qt/Basic_viewer_qt.h>
 
 // Functor used by SimpleLCCViewerQt to colorize of not elements.
@@ -107,7 +110,7 @@ struct MyDrawingFunctorLCC
 };
 
 
-class Viewer : public Basic_viewer_qt
+class Viewer : public CGAL::Basic_viewer_qt
 {
   Q_OBJECT
 
@@ -123,8 +126,8 @@ public Q_SLOTS:
   void sceneChanged();
 
 private:
-  const DrawingFunctorLCC &m_drawing_functor;
-  bool m_nofaces,  m_random_face_color;
+  const MyDrawingFunctorLCC &m_drawing_functor_;
+  bool m_nofaces_,  m_random_face_color_;
   Scene* scene;
   bool m_previous_scene_empty;
 };