diff --git a/SierpinskiDA.cc b/SierpinskiDA.cc
index be95cfe..4745f8e 100644
--- a/SierpinskiDA.cc
+++ b/SierpinskiDA.cc
@@ -16,13 +16,38 @@ SierpinskiDA::SierpinskiDA(const Glib::RefPtr<const Gdk::GL::Config> & config)
              | Gdk::SCROLL_MASK);
 }
 
-bool SierpinskiDA::draw()
+void SierpinskiDA::regenerate(int npts)
+{
+    gl_begin();
+    glNewList(m_dl, GL_COMPILE);
+    glBegin(GL_QUADS);
+    glVertex3f(1, 0, 1);
+    glVertex3f(-1, 0, 1);
+    glVertex3f(-1, 0, -1);
+    glVertex3f(1, 0, -1);
+    glEnd();
+    glEndList();
+    gl_end();
+}
+
+bool SierpinskiDA::gl_begin()
 {
     Glib::RefPtr<Gdk::GL::Window> glwindow = get_gl_window();
-    if (!glwindow->gl_begin(get_gl_context()))
+    return glwindow->gl_begin(get_gl_context());
+}
+
+void SierpinskiDA::gl_end()
+{
+    Glib::RefPtr<Gdk::GL::Window> glwindow = get_gl_window();
+    glwindow->gl_end();
+}
+
+bool SierpinskiDA::draw()
+{
+    if (!gl_begin())
         return false;
 
-    glClearColor(0.1, 0.6, 1.0, 1.0);
+    glClearColor(0.0, 0.0, 0.0, 1.0);
     glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
     glMatrixMode(GL_PROJECTION);
     glLoadIdentity();
@@ -32,11 +57,14 @@ bool SierpinskiDA::draw()
               0, 0, 0,
               0, 0, 1);
 
-    if (glwindow->is_double_buffered())
-        glwindow->swap_buffers();
+    glCallList(m_dl);
+
+    if (get_gl_window()->is_double_buffered())
+        get_gl_window()->swap_buffers();
     else
         glFlush();
 
+    gl_end();
     return true;
 }
 
@@ -65,15 +93,15 @@ void SierpinskiDA::on_realize()
 {
     Gtk::GL::DrawingArea::on_realize();
 
-    Glib::RefPtr<Gdk::GL::Window> glwindow = get_gl_window();
-    glwindow->get_window()->set_cursor(Gdk::Cursor(Gdk::CROSSHAIR));
-
-    if (!glwindow->gl_begin(get_gl_context()))
+    if (gl_begin())
         return;
 
     glViewport(0, 0, get_width(), get_height());
+    m_dl = glGenLists(1);
 
-    glwindow->gl_end();
+    gl_end();
+
+    regenerate(10);
 }
 
 /*
@@ -81,14 +109,12 @@ void SierpinskiDA::on_realize()
  */
 bool SierpinskiDA::on_configure_event(GdkEventConfigure * event)
 {
-    Glib::RefPtr<Gdk::GL::Window> glwindow = get_gl_window();
-
-    if (!glwindow->gl_begin(get_gl_context()))
+    if (gl_begin())
         return false;
 
     glViewport(0, 0, get_width(), get_height());
 
-    glwindow->gl_end();
+    gl_end();
 
     return true;
 }
diff --git a/SierpinskiDA.h b/SierpinskiDA.h
index 7bc788f..cea2d53 100644
--- a/SierpinskiDA.h
+++ b/SierpinskiDA.h
@@ -8,14 +8,18 @@ class SierpinskiDA : public Gtk::GL::DrawingArea
 {
     public:
         SierpinskiDA(const Glib::RefPtr<const Gdk::GL::Config> & config);
+        void regenerate(int npts);
 
     protected:
         int m_x, m_y;
+        int m_dl;
 
         virtual bool draw();
         virtual void on_realize();
         virtual bool on_configure_event(GdkEventConfigure * event);
         virtual bool on_expose_event(GdkEventExpose * event);
+        bool gl_begin();
+        void gl_end();
 
         /* signal handlers */
         virtual bool on_motion_notify_event(GdkEventMotion * event);