HTMTR
      +----------
GLUTL | GZLXMMXUQ
       -GLUTL
        =====
         MNWYM
        -RJWVQ
         =====
         HYVNZX
        -HNNTXZ
         ======
           MGTPU
          -RJWVQ
           =====
           HGJPHQ
          -HHZMHR
           ======
            HHHVT

base: 16
letters: GHJLMNPQRTUVWXYZ
difficulty: medium