YMVR
      +---------
MHLWQ | LPTWQYYZ
       -ZHVRT
        =====
        NQPYRY
       -NUJHPG
        ======
         YQUMRY
        -YYJYWR
         ======
          UPNTGZ
         -UNWQPT
          ======
           UMQYW

base: 16
letters: GHJLMNPQRTUVWXYZ
difficulty: hard
missing: X