ZHGX
      +---------
LZZTZ | UXXJHMRL
       -WYHTY
        =====
        QRWGNM
       -QHVZNG
        ======
         ZWHURR
        -ZHRNQH
         ======
          NRGMZL
         -NRJTYP
          ======
            TQYU

base: 16
letters: GHJLMNPQRTUVWXYZ
difficulty: hard