private void markForDamage(Element e, Batch <Element> inRange) {
    if (e == null || e.flaggedWith() != null) return ;
    e.flagWith(inRange) ;
    inRange.add(e) ;
    if (e instanceof Boardable) for (Mobile m : ((Boardable) e).inside()) {
      markForDamage(m, inRange) ;
    }
  }