diff --git a/Packages/Nef_S2/TODO b/Packages/Nef_S2/TODO
index 1b00335f5e4..237ecd6b074 100644
--- a/Packages/Nef_S2/TODO
+++ b/Packages/Nef_S2/TODO
@@ -1,4 +1,6 @@
 Possible Improvements for future releases are
 
 1) introduce clean spherical kernel trais 
+2) clean up edge pair architecture
+3) introduce filtering
 
diff --git a/Packages/Nef_S2/description.txt b/Packages/Nef_S2/description.txt
index 6f67e9697e2..d0b50d6de99 100644
--- a/Packages/Nef_S2/description.txt
+++ b/Packages/Nef_S2/description.txt
@@ -1 +1 @@
-Nef polyhedra in the plane
+Nef polyhedra in the sphere surface
diff --git a/Packages/Nef_S2/examples/Nef_S2/README b/Packages/Nef_S2/examples/Nef_S2/README
new file mode 100644
index 00000000000..9c03ba1b623
--- /dev/null
+++ b/Packages/Nef_S2/examples/Nef_S2/README
@@ -0,0 +1,13 @@
+
+  construction.C
+
+  a simple example showing construction syntax
+
+HowTo build these demos:
+
+  1) Set the environment variable CGAL_MAKEFILE to the makefile 
+     of choice after the configuration of CGAL. Makefiles 
+     (configurations) can be found in ../../make
+
+  2) Engage (type "make <return>")
+     
diff --git a/Packages/Nef_S2/examples/Nef_S2/construction.C b/Packages/Nef_S2/examples/Nef_S2/construction.C
new file mode 100644
index 00000000000..105e6b5f893
--- /dev/null
+++ b/Packages/Nef_S2/examples/Nef_S2/construction.C
@@ -0,0 +1,33 @@
+// file : examples/Nef_S2/construction.C
+
+#include <CGAL/Gmpz.h>
+#include <CGAL/Homogeneous.h>
+#include <CGAL/Nef_polyhedron_S2.h>
+
+typedef CGAL::Gmpz RT;
+typedef CGAL::Homogeneous<RT> Kernel;
+typedef CGAL::Nef_polyhedron_S2<Kernel> Nef_polyhedron;
+typedef Nef_polyhedron::Sphere_point Sphere_point;
+typedef Nef_polyhedron::Sphere_segment Sphere_segment;
+typedef Nef_polyhedron::Sphere_circle Sphere_circle;
+
+int main() {
+
+  Nef_polyhedron N1(Nef_polyhedron::COMPLETE);
+
+  Sphere_circle c(1,1,1); // c : x + y + z = 0
+  Nef_polyhedron N2(c,Nef_polyhedron::INCLUDED);
+  Nef_polyhedron N3 = N2.complement();
+  CGAL_assertion(N1 == N2.join(N3));
+
+  Sphere_point   p1(1,0,0), p2(0,1,0), p3(0,0,1);
+  Sphere_segment s1(p1,p2), s2(p2,p3), s3(p3,p1);
+  Sphere_segment triangle[3] = { s1, s2, s3 };
+  Nef_polyhedron N4(triangle, triangle+3);
+  Nef_polyhedron N5 = N2.intersection(N4);
+  CGAL_assertion(N5 <= N2 && N5 <= N4);
+
+  return 0;
+}
+
+
diff --git a/Packages/Nef_S2/examples/Nef_S2/makefile b/Packages/Nef_S2/examples/Nef_S2/makefile
new file mode 100644
index 00000000000..10f2920ab27
--- /dev/null
+++ b/Packages/Nef_S2/examples/Nef_S2/makefile
@@ -0,0 +1,59 @@
+# Created by the script create_makefile
+# This is the makefile for compiling a CGAL application.
+
+#---------------------------------------------------------------------#
+#                    include platform specific settings
+#---------------------------------------------------------------------#
+# Choose the right include file from the <cgalroot>/make directory.
+
+# CGAL_MAKEFILE = ENTER_YOUR_INCLUDE_MAKEFILE_HERE
+include $(CGAL_MAKEFILE)
+
+#---------------------------------------------------------------------#
+#                    compiler flags
+#---------------------------------------------------------------------#
+
+CXXFLAGS = \
+           $(EXTRA_FLAGS) \
+           $(CGAL_CXXFLAGS) \
+           $(LONG_NAME_PROBLEM_CXXFLAGS) \
+           $(DEBUG_OPT)
+
+#---------------------------------------------------------------------#
+#                    linker flags
+#---------------------------------------------------------------------#
+
+LIBPATH = \
+          $(CGAL_LIBPATH)
+
+LDFLAGS = \
+          $(LONG_NAME_PROBLEM_LDFLAGS) \
+          $(CGAL_LDFLAGS)
+
+#---------------------------------------------------------------------#
+#                    target entries
+#---------------------------------------------------------------------#
+
+all:    \
+	construction$(EXE_EXT) \
+	simple$(EXE_EXT) 
+
+construction$(EXE_EXT): construction$(OBJ_EXT)
+	$(CGAL_CXX) $(LIBPATH) $(EXE_OPT)construction \
+	construction$(OBJ_EXT) $(LDFLAGS)
+
+simple$(EXE_EXT): simple$(OBJ_EXT)
+	$(CGAL_CXX) $(LIBPATH) $(EXE_OPT)simple \
+	simple$(OBJ_EXT) $(LDFLAGS)
+
+clean: \
+                   construction.clean \
+                   simple.clean 
+
+#---------------------------------------------------------------------#
+#                    suffix rules
+#---------------------------------------------------------------------#
+
+.C$(OBJ_EXT):
+	$(CGAL_CXX) $(CXXFLAGS) $(OBJ_OPT) $<
+
diff --git a/Packages/Nef_S2/examples/Nef_S2/simple.C b/Packages/Nef_S2/examples/Nef_S2/simple.C
new file mode 100644
index 00000000000..68bef4afab3
--- /dev/null
+++ b/Packages/Nef_S2/examples/Nef_S2/simple.C
@@ -0,0 +1,18 @@
+// file : examples/Nef_S2/simple.C
+
+#include <CGAL/Gmpz.h>
+#include <CGAL/Homogeneous.h>
+#include <CGAL/Nef_polyhedron_S2.h>
+
+typedef CGAL::Gmpz RT;
+typedef CGAL::Homogeneous<RT> Kernel;
+typedef CGAL::Nef_polyhedron_S2<Kernel> Nef_polyhedron;
+typedef Nef_polyhedron::Sphere_circle Sphere_circle;
+
+int main()
+{
+  Nef_polyhedron N1(Sphere_circle(1,0,0));
+  Nef_polyhedron N2(Sphere_circle(0,1,0), Nef_polyhedron::EXCLUDED);
+  Nef_polyhedron N3 = N1 * N2; // line (*)
+  return 0;
+}
diff --git a/Packages/Nef_S2/include/CGAL/Nef_S2/SM_decorator.h b/Packages/Nef_S2/include/CGAL/Nef_S2/SM_decorator.h
index e08fba87b4e..e1eb83d69b5 100644
--- a/Packages/Nef_S2/include/CGAL/Nef_S2/SM_decorator.h
+++ b/Packages/Nef_S2/include/CGAL/Nef_S2/SM_decorator.h
@@ -298,7 +298,7 @@ Face_handle new_face() const
 
 void delete_vertex_only(Vertex_handle v) const
 /*{\Mop deletes |v| without any connectivity update.}*/
-{ return psm_->delete_vertex(v); }
+{ psm_->delete_vertex(v); }
 
 void delete_edge_pair_only(Halfedge_handle e) const
 /*{\Mop deletes |e| and its twin without any connectivity update.}*/
@@ -310,7 +310,7 @@ void delete_halfedge_only(Halfedge_handle e) const
 
 void delete_face_only(Face_handle f) const
 /*{\Mop deletes |f| without any connectivity update.}*/
-{ return psm_->delete_face(f); }
+{ psm_->delete_face(f); }
 
 void delete_loop_only() const
 /*{\Mop deletes the loop and its twin without any connectivity update.}*/ 
diff --git a/Packages/Nef_S2/include/CGAL/Nef_S2/SM_io_parser.h b/Packages/Nef_S2/include/CGAL/Nef_S2/SM_io_parser.h
index 4e5b334c3cf..460e1525016 100644
--- a/Packages/Nef_S2/include/CGAL/Nef_S2/SM_io_parser.h
+++ b/Packages/Nef_S2/include/CGAL/Nef_S2/SM_io_parser.h
@@ -66,11 +66,11 @@ class SM_io_parser : public Decorator_
 
 public:
 /*{\Mcreation 3}*/
-SM_io_parser(istream& is, const Base& D);
+SM_io_parser(std::istream& is, const Base& D);
 /*{\Mcreate creates an instance |\Mvar| of type |\Mname|
 to input |H| from |is|.}*/
 
-SM_io_parser(ostream& os, const Base& D);
+SM_io_parser(std::ostream& os, const Base& D);
 /*{\Mcreate creates an instance |\Mvar| of type |\Mname|
 to output |H| to |os|.}*/
 
@@ -101,7 +101,7 @@ static void dump(const Decorator_& D, std::ostream& os = cerr);
 
 template <typename Decorator_>
 SM_io_parser<Decorator_>::
-SM_io_parser(istream& iin, const Decorator_& H) :
+SM_io_parser(std::istream& iin, const Decorator_& H) :
   Base(H), in(iin), out(std::cout), verbose(0), 
   vn(0), en(0), fn(0), ln(0)
 { clear(); }
diff --git a/Packages/Nef_S2/include/CGAL/Nef_S2/Sphere_geometry_OGL.h b/Packages/Nef_S2/include/CGAL/Nef_S2/Sphere_geometry_OGL.h
index 4ef2c3aa919..a2ec1d6ab17 100644
--- a/Packages/Nef_S2/include/CGAL/Nef_S2/Sphere_geometry_OGL.h
+++ b/Packages/Nef_S2/include/CGAL/Nef_S2/Sphere_geometry_OGL.h
@@ -769,7 +769,7 @@ void init()
   glMaterialfv(GL_FRONT_AND_BACK, GL_DIFFUSE, mat_diffuse );
   glMaterialfv(GL_FRONT_AND_BACK, GL_SPECULAR, mat_specular );
   glMaterialfv(GL_FRONT_AND_BACK, GL_SHININESS, mat_shininess );
-//#define SCREENSHOTS
+#define SCREENSHOTS
 #ifdef SCREENSHOTS
   GLfloat mat_emission[] = { 0.1, 0.1, 0.2, 0.0 };
   glMaterialfv(GL_FRONT, GL_EMISSION, mat_emission);
diff --git a/Packages/Nef_S2/noweb/Sphere_geometry.lw b/Packages/Nef_S2/noweb/Sphere_geometry.lw
deleted file mode 100644
index 274eff0ae25..00000000000
--- a/Packages/Nef_S2/noweb/Sphere_geometry.lw
+++ /dev/null
@@ -1,28 +0,0 @@
-%------------------------------------------------------------------------------
-%KILLSTART
-%LDEL TRACE.*?\)\;
-\documentclass[a4paper]{article}
-\usepackage{amsmath,MyLweb,version}
-\input{defs}
-\excludeversion{ignorecodeparts}
-
-\begin{document}
-\title{Spherical Geometry}
-\author{Michael Seel}
-\maketitle
-\tableofcontents
-\newpage
-
-\section{The manual page}
-
-\input{manpages/Sphere_point.man}
-\input{manpages/Sphere_segment.man}
-\input{manpages/Sphere_circle.man}
-\input{manpages/Sphere_direction.man}
-\input{manpages/Sphere_triangle.man}
-\newpage
-
-\bibliographystyle{alpha}
-\bibliography{diss}
-\end{document}
-
diff --git a/Packages/Nef_S2/test/Nef_S2/Sphere_geometry-test.C b/Packages/Nef_S2/test/Nef_S2/Sphere_geometry-test.C
index 40db5ea83fe..4020206dc38 100644
--- a/Packages/Nef_S2/test/Nef_S2/Sphere_geometry-test.C
+++ b/Packages/Nef_S2/test/Nef_S2/Sphere_geometry-test.C
@@ -55,7 +55,7 @@ int main()
   L.push_back(s2);
   L.push_back(s3);
   SCircle pos_xy(0,0,1);
-  partition( pos_xy, L.begin(), L.end(), Lp);
+  CGAL::partition( pos_xy, L.begin(), L.end(), Lp);
   for (it = Lp.begin(); it != Lp.end(); ++it) {
     std::cout << *it << std::endl;
   }