(a b c
   (x y z
      (a b c
         (x y z
            (a b c
               (x y z
                  (a b c
                     (x y z
                        (a b c
                           (x y z
                              (a b c
                                 (x y z
                                    (a b c
                                       (x y z
                                          (a b c
                                             (x y z
                                                (a b c
                                                   (x y z
                                                      (a b c)))))))))))))))))))