Bloccaggio in acciaio

  *******     *      *****      *     *******   *****   
  *          **     *     *    * *    *        *     *  
  *         * *           *    * *    *        *     *  
  ****        *          *    *   *   ****      *****   
  *           *        **     *****   *        *     *  
  *           *      **      *     *  *        *     *  
  *******  *******  *******  *     *  *******   *****