docs: private int countAreas(Area a, Rectangular r)
      {
          int ret = 0;
          
          for (int i = 0; i < a.getChildCount(); i++)
          {
              Area n = a.getChildAt(i);
              if (a.getTopology().getPosition(n).intersects(r))
                  ret++;
          }
          return ret;
      }