????????
      +---------
MGXHY | ZJLPTTLZ
       -WZPUL
        =====
         YXVYT
        -VQYZN
         =====
          UQTUL
         -XPQVU
          =====
          MRZNZZ
         - GWZWR
          ======
          ??????

base: 16
letters: GHJLMNPQRTUVWXYZ
difficulty: hard