@Override
 public void draw(SimGraphics arg) {
   // TODO Auto-generated method stub
   if (img != null) {
     arg.drawImageToFit(img);
   } else {
     arg.drawFastRect(new Color(255, 0, 0));
   }
 }
 public void draw(SimGraphics g) {
   g.drawFastRoundRect(Color.red);
 }