diff --git a/Envelope_3/examples/Envelope_3/envelope_planes.cpp b/Envelope_3/examples/Envelope_3/envelope_planes.cpp
index 6595f5e9585..ce8e77b6fe4 100644
--- a/Envelope_3/examples/Envelope_3/envelope_planes.cpp
+++ b/Envelope_3/examples/Envelope_3/envelope_planes.cpp
@@ -1,81 +1,63 @@
 //! \file examples/Envelope_3/ex_envelope_planes.cpp
 // Constructing the lower and the upper envelope of a set of planes.
 
+#include <iostream>
+#include <list>
+
 #include <CGAL/Exact_rational.h>
 #include <CGAL/Cartesian.h>
 #include <CGAL/Env_plane_traits_3.h>
 #include <CGAL/envelope_3.h>
-#include <iostream>
-#include <list>
-
-typedef CGAL::Exact_rational                             Number_type;
-typedef CGAL::Cartesian<Number_type>                     Kernel;
-typedef Kernel::Plane_3                                  Plane_3;
-typedef CGAL::Env_plane_traits_3<Kernel>                 Traits_3;
-typedef Traits_3::Surface_3                              Surface_3;
-typedef CGAL::Envelope_diagram_2<Traits_3>               Envelope_diagram_2;
 
+using Number_type = CGAL::Exact_rational;
+using Kernel = CGAL::Cartesian<Number_type>;
+using Plane_3 = Kernel::Plane_3;
+using Traits_3 = CGAL::Env_plane_traits_3<Kernel>;
+using Surface_3 = Traits_3::Surface_3;
+using Envelope_diagram_2 = CGAL::Envelope_diagram_2<Traits_3>;
 
 /* Auxiliary function - print the features of the given envelope diagram. */
-void print_diagram (const Envelope_diagram_2& diag)
-{
+void print_diagram(const Envelope_diagram_2& diag) {
   // Go over all arrangement faces.
-  Envelope_diagram_2::Face_const_iterator            fit;
-  Envelope_diagram_2::Ccb_halfedge_const_circulator  ccb;
-  Envelope_diagram_2::Surface_const_iterator         sit;
-
-  for (fit = diag.faces_begin(); fit != diag.faces_end(); ++fit)
-  {
+  for (auto fit = diag.faces_begin(); fit != diag.faces_end(); ++fit) {
     // Print the face boundary.
 
     // Print the vertices along the outer boundary of the face.
-    ccb = fit->outer_ccb();
-    std::cout << "[Face]  ";
-    do
-    {
-      if(!ccb->is_fictitious())
-        std::cout << '(' << ccb->curve() << ") ";
-      ++ccb;
-    } while (ccb != fit->outer_ccb());
+    auto ccb = fit->outer_ccb();
+    std::cout << "[Face] ";
+    do if (!ccb->is_fictitious()) std::cout << '(' << ccb->curve() << ") ";
+    while (++ccb != fit->outer_ccb());
 
     // Print the planes that induce the envelope on this face.
-    std::cout << "-->  " << fit->number_of_surfaces()
-              << " planes:";
+    std::cout << "--> " << fit->number_of_surfaces() << " planes:";
 
-    for (sit = fit->surfaces_begin(); sit != fit->surfaces_end(); ++sit)
+    for (auto sit = fit->surfaces_begin(); sit != fit->surfaces_end(); ++sit)
       std::cout << ' ' << sit->plane();
     std::cout << std::endl;
   }
-
-  return;
 }
 
 /* The main program: */
-int main ()
-{
+int main() {
   // Construct the input planes.
-  std::list<Surface_3>   planes;
+  std::list<Surface_3> planes;
 
-  planes.push_back (Surface_3(Plane_3(0, -1, 1, 0)));
-  planes.push_back (Surface_3(Plane_3(-1, 0, 1, 0)));
-  planes.push_back (Surface_3(Plane_3(0, 1 , 1, 0)));
-  planes.push_back (Surface_3(Plane_3(1, 0, 1,  0)));
+  planes.push_back(Surface_3(Plane_3(0, -1, 1, 0)));
+  planes.push_back(Surface_3(Plane_3(-1, 0, 1, 0)));
+  planes.push_back(Surface_3(Plane_3(0, 1 , 1, 0)));
+  planes.push_back(Surface_3(Plane_3(1, 0, 1,  0)));
 
   // Compute and print the minimization diagram.
-  Envelope_diagram_2      min_diag;
-
-  CGAL::lower_envelope_3 (planes.begin(), planes.end(), min_diag);
-
+  Envelope_diagram_2 min_diag;
+  CGAL::lower_envelope_3(planes.begin(), planes.end(), min_diag);
   std::cout << std::endl << "The minimization diagram:" << std::endl;
-  print_diagram (min_diag);
+  print_diagram(min_diag);
 
   // Compute and print the maximization diagram.
-  Envelope_diagram_2      max_diag;
-
-  CGAL::upper_envelope_3 (planes.begin(), planes.end(), max_diag);
-
+  Envelope_diagram_2 max_diag;
+  CGAL::upper_envelope_3(planes.begin(), planes.end(), max_diag);
   std::cout << std::endl << "The maximization diagram:" << std::endl;
   print_diagram (max_diag);
 
-  return (0);
+  return 0;
 }
diff --git a/Envelope_3/examples/Envelope_3/envelope_spheres.cpp b/Envelope_3/examples/Envelope_3/envelope_spheres.cpp
index 41c9bb4568f..e71fb5bba14 100644
--- a/Envelope_3/examples/Envelope_3/envelope_spheres.cpp
+++ b/Envelope_3/examples/Envelope_3/envelope_spheres.cpp
@@ -5,47 +5,44 @@
 
 #ifndef CGAL_USE_CORE
 #include <iostream>
-int main()
-{
+int main() {
   std::cout << "Sorry, this example needs CORE ..." << std::endl;
   return 0;
 }
 #else
 
+#include <iostream>
+#include <list>
+#include <chrono>
+
 #include <CGAL/Cartesian.h>
 #include <CGAL/CORE_algebraic_number_traits.h>
 #include <CGAL/Arr_conic_traits_2.h>
 #include <CGAL/Env_sphere_traits_3.h>
 #include <CGAL/envelope_3.h>
-#include <CGAL/Timer.h>
-#include <iostream>
-#include <list>
 
-typedef CGAL::CORE_algebraic_number_traits            Nt_traits;
-typedef Nt_traits::Rational                           Rational;
-typedef Nt_traits::Algebraic                          Algebraic;
-typedef CGAL::Cartesian<Rational>                     Rat_kernel;
-typedef Rat_kernel::Point_3                           Rat_point_3;
-typedef CGAL::Cartesian<Algebraic>                    Alg_kernel;
+using Nt_traits = CGAL::CORE_algebraic_number_traits;
+using Rational = Nt_traits::Rational;
+using Algebraic = Nt_traits::Algebraic;
+using Rat_kernel = CGAL::Cartesian<Rational>;
+using Rat_point_3 = Rat_kernel::Point_3;
+using Alg_kernel = CGAL::Cartesian<Algebraic>;
 
-typedef CGAL::Arr_conic_traits_2<Rat_kernel, Alg_kernel, Nt_traits>
-                                                      Conic_traits_2;
+using Conic_traits_2 =
+  CGAL::Arr_conic_traits_2<Rat_kernel, Alg_kernel, Nt_traits>;
 
-typedef CGAL::Env_sphere_traits_3<Conic_traits_2>     Traits_3;
-typedef Traits_3::Surface_3                           Sphere_3;
-typedef CGAL::Envelope_diagram_2<Traits_3>            Envelope_diagram_2;
+using Traits_3 = CGAL::Env_sphere_traits_3<Conic_traits_2>;
+using Sphere_3 = Traits_3::Surface_3;
+using Envelope_diagram_2 = CGAL::Envelope_diagram_2<Traits_3>;
 
-int main(int argc, char **argv)
-{
+int main(int argc, char* argv[]) {
   // Get the name of the input file from the command line, or use the default
   // fan_grids.dat file if no command-line parameters are given.
-  const char * filename = (argc > 1) ? argv[1] : "spheres.dat";
+  const char* filename = (argc > 1) ? argv[1] : "spheres.dat";
 
   // Open the input file.
-  std::ifstream     in_file(filename);
-
-  if (! in_file.is_open())
-  {
+  std::ifstream in_file(filename);
+  if (! in_file.is_open()) {
     std::cerr << "Failed to open " << filename << " ..." << std::endl;
     return 1;
   }
@@ -57,37 +54,28 @@ int main(int argc, char **argv)
   // <x_2> <y_2> <x_2> <R_2>       // center and squared radious of sphere #2.
   //   :     :     :     :
   // <x_n> <y_n> <x_n> <R_n>       // center and squared radious of sphere #n.
-  int                   n = 0;
-  std::list<Sphere_3>   spheres;
-  int                   x = 0, y = 0, z = 0, sqr_r = 0;
-  int                   i;
-
+  int n = 0;
+  std::list<Sphere_3> spheres;
+  int x = 0, y = 0, z = 0, sqr_r = 0;
   in_file >> n;
-  for (i = 0; i < n; ++i)
-  {
+  for (int i = 0; i < n; ++i) {
     in_file >> x >> y >> z >> sqr_r;
     spheres.push_back(Sphere_3(Rat_point_3(x, y, z), Rational(sqr_r)));
   }
   in_file.close();
+  std::cout << "Constructing the lower envelope of " << n << " spheres.\n";
 
   // Compute the lower envelope.
-  Envelope_diagram_2    min_diag;
-  CGAL::Timer           timer;
-
-  std::cout << "Constructing the lower envelope of "
-            << n << " spheres." << std::endl;
-
-  timer.start();
+  Envelope_diagram_2 min_diag;
+  auto start = std::chrono::system_clock::now();
   CGAL::lower_envelope_3(spheres.begin(), spheres.end(), min_diag);
-  timer.stop();
+  std::chrono::duration<double> secs = std::chrono::system_clock::now() - start;
 
   // Print the dimensions of the minimization diagram.
   std::cout << "V = " << min_diag.number_of_vertices()
-            << ",  E = " << min_diag.number_of_edges()
-            << ",  F = " << min_diag.number_of_faces() << std::endl;
-
-  std::cout << "Construction took " << timer.time()
-            << " seconds." << std::endl;
+            << ", E = " << min_diag.number_of_edges()
+            << ", F = " << min_diag.number_of_faces() << std::endl;
+  std::cout << "Construction took " << secs.count() << " seconds.\n";
 
   return 0;
 }
diff --git a/Envelope_3/examples/Envelope_3/envelope_triangles.cpp b/Envelope_3/examples/Envelope_3/envelope_triangles.cpp
index b8715c10b42..b16a229f290 100644
--- a/Envelope_3/examples/Envelope_3/envelope_triangles.cpp
+++ b/Envelope_3/examples/Envelope_3/envelope_triangles.cpp
@@ -1,110 +1,82 @@
 //! \file examples/Envelope_3/ex_envelope_triangles.cpp
 // Constructing the lower and the upper envelope of a set of triangles.
 
+#include <iostream>
+#include <list>
+
 #include <CGAL/Exact_rational.h>
 #include <CGAL/Cartesian.h>
 #include <CGAL/Env_triangle_traits_3.h>
 #include <CGAL/Env_surface_data_traits_3.h>
 #include <CGAL/envelope_3.h>
-#include <iostream>
-#include <list>
 
-typedef CGAL::Exact_rational                             Number_type;
-typedef CGAL::Cartesian<Number_type>                     Kernel;
-typedef CGAL::Env_triangle_traits_3<Kernel>              Traits_3;
-typedef Kernel::Point_3                                  Point_3;
-typedef Traits_3::Surface_3                              Triangle_3;
-typedef CGAL::Env_surface_data_traits_3<Traits_3, char>  Data_traits_3;
-typedef Data_traits_3::Surface_3                         Data_triangle_3;
-typedef CGAL::Envelope_diagram_2<Data_traits_3>          Envelope_diagram_2;
+using Number_type = CGAL::Exact_rational;
+using Kernel = CGAL::Cartesian<Number_type>;
+using Traits_3 = CGAL::Env_triangle_traits_3<Kernel>;
+using Point_3 = Kernel::Point_3;
+using Triangle_3 = Traits_3::Surface_3;
+using Data_traits_3 = CGAL::Env_surface_data_traits_3<Traits_3, char>;
+using Data_triangle_3 = Data_traits_3::Surface_3;
+using Envelope_diagram_2 = CGAL::Envelope_diagram_2<Data_traits_3>;
 
 /* Auxiliary function - print the features of the given envelope diagram. */
-void print_diagram (const Envelope_diagram_2& diag)
-{
+void print_diagram(const Envelope_diagram_2& diag) {
   // Go over all arrangement faces.
-  Envelope_diagram_2::Face_const_iterator            fit;
-  Envelope_diagram_2::Ccb_halfedge_const_circulator  ccb;
-  Envelope_diagram_2::Surface_const_iterator         sit;
-
-  for (fit = diag.faces_begin(); fit != diag.faces_end(); ++fit)
-  {
+  for (auto fit = diag.faces_begin(); fit != diag.faces_end(); ++fit) {
     // Print the face boundary.
-    if (fit->is_unbounded())
-    {
-      std::cout << "[Unbounded face]";
-    }
-    else
-    {
+    if (fit->is_unbounded()) std::cout << "[Unbounded face]";
+    else {
       // Print the vertices along the outer boundary of the face.
-      ccb = fit->outer_ccb();
+      auto ccb = fit->outer_ccb();
       std::cout << "[Face]  ";
-      do
-      {
-        std::cout << '(' << ccb->target()->point() << ")  ";
-        ++ccb;
-      } while (ccb != fit->outer_ccb());
+      do std::cout << '(' << ccb->target()->point() << ")  ";
+      while (++ccb != fit->outer_ccb());
     }
 
     // Print the labels of the triangles that induce the envelope on this face.
-    std::cout << "-->  " << fit->number_of_surfaces()
-              << " triangles:";
+    std::cout << "-->  " << fit->number_of_surfaces() << " triangles:";
 
-    for (sit = fit->surfaces_begin(); sit != fit->surfaces_end(); ++sit)
+    for (auto sit = fit->surfaces_begin(); sit != fit->surfaces_end(); ++sit)
       std::cout << ' ' << sit->data();
     std::cout << std::endl;
   }
 
   // Go over all arrangement edges.
-  Envelope_diagram_2::Edge_const_iterator            eit;
+  Envelope_diagram_2::Edge_const_iterator eit;
 
-  for (eit = diag.edges_begin(); eit != diag.edges_end(); ++eit)
-  {
+  for (auto eit = diag.edges_begin(); eit != diag.edges_end(); ++eit) {
     // Print the labels of the triangles that induce the envelope on this edge.
     std::cout << "[Edge]  (" << eit->source()->point()
-              << ")  (" << eit->target()->point()
-              << ")  -->  " << eit->number_of_surfaces()
+              << ") (" << eit->target()->point()
+              << ") -->  " << eit->number_of_surfaces()
               << " triangles:";
 
-    for (sit = eit->surfaces_begin(); sit != eit->surfaces_end(); ++sit)
+    for (auto sit = eit->surfaces_begin(); sit != eit->surfaces_end(); ++sit)
       std::cout << ' ' << sit->data();
     std::cout << std::endl;
   }
-
-  return;
 }
 
 /* The main program: */
-int main ()
-{
+int main() {
   // Construct the input triangles, makred A and B.
-  std::list<Data_triangle_3>   triangles;
-
-  triangles.push_back (Data_triangle_3 (Triangle_3 (Point_3 (0, 0, 0),
-                                                    Point_3 (0, 6, 0),
-                                                    Point_3 (5, 3, 4)),
-                                        'A'));
-  triangles.push_back (Data_triangle_3 (Triangle_3 (Point_3 (6, 0, 0),
-                                                    Point_3 (6, 6, 0),
-                                                    Point_3 (1, 3, 4)),
-                                        'B'));
+  std::list<Data_triangle_3> triangles;
+  auto t1 = Triangle_3(Point_3 (0, 0, 0), Point_3 (0, 6, 0), Point_3 (5, 3, 4));
+  triangles.push_back(Data_triangle_3(t1, 'A'));
+  auto t2 = Triangle_3(Point_3 (6, 0, 0), Point_3 (6, 6, 0), Point_3 (1, 3, 4));
+  triangles.push_back(Data_triangle_3(t2, 'B'));
 
   // Compute and print the minimization diagram.
-  Envelope_diagram_2      min_diag;
-
-  CGAL::lower_envelope_3 (triangles.begin(), triangles.end(),
-                          min_diag);
-
+  Envelope_diagram_2 min_diag;
+  CGAL::lower_envelope_3(triangles.begin(), triangles.end(), min_diag);
   std::cout << std::endl << "The minimization diagram:" << std::endl;
-  print_diagram (min_diag);
+  print_diagram(min_diag);
 
   // Compute and print the maximization diagram.
-  Envelope_diagram_2      max_diag;
-
-  CGAL::upper_envelope_3 (triangles.begin(), triangles.end(),
-                          max_diag);
-
+  Envelope_diagram_2 max_diag;
+  CGAL::upper_envelope_3 (triangles.begin(), triangles.end(), max_diag);
   std::cout << std::endl << "The maximization diagram:" << std::endl;
   print_diagram (max_diag);
 
-  return (0);
+  return 0;
 }