<Binary Space Partitioning Tree Display>=
  public void DisplayTree(root) {
   if (null != root) {
      if (viewer in front of root) {
         DisplayTree(root.back);
         root.displayPolygon();
         DisplayTree(root.front);
   }
   else {
         DisplayTree(root.front);
         root.displayPolygon();
         DisplayTree(root.back);
   }
 }
}

• <Binary Space Partitioning Tree Display>: D1