private void addLines() {
   layer.addChild(l1 = PPath.createLine(0, 0, 0, 800));
   layer.addChild(l2 = PPath.createLine(0, 0, 0, 800));
   l1.setStrokePaint(Color.lightGray);
   l2.setStrokePaint(Color.lightGray);
   l1.setPickable(false);
   l2.setPickable(false);
 }