public void update() {
   updateThisOne();
   if (children != null) {
     for (GeometryObject geometryObject : children) {
       geometryObject.update();
     }
   }
 }
 @Override
 public void draw(IDrawContext drawContext) {
   drawThisOne(drawContext);
   if (children != null) {
     for (GeometryObject geometryObject : children) {
       geometryObject.draw(drawContext);
     }
   }
 }