WMGP
      +---------
QPLLZ | UMXUHGNU
       -QPLLZ
        =====
         VYZMG
        -TJJVL
         =====
         NMHUJN
        -NYVNLJ
         ======
          WJWLPU
         -WRHHPR
          ======
           MTQXG

base: 16
letters: GHJLMNPQRTUVWXYZ
difficulty: hard