public static Drilling nextDrillFor(Actor actor) {
    if (actor.base() == null) return null ;
    if (! (actor.mind.work() instanceof Venue)) return null ;
    
    final World world = actor.world() ;
    final Batch <DrillYard> yards = new Batch <DrillYard> () ;
    world.presences.sampleFromKey(actor, world, 5, yards, DrillYard.class) ;
    
    final Choice choice = new Choice(actor) ;
    for (DrillYard yard : yards) if (yard.base() == actor.base()) {
      ///I.sayAbout(actor, "Can drill at "+yard) ;
      final Drilling drilling = new Drilling(actor, yard) ;
      choice.add(drilling) ;
    }
    return (Drilling) choice.pickMostUrgent() ;
  }