LZVU
      +---------
LWHHG | MQLNGLMP
       -LWHHG
        =====
         UGZJL
        -VTMMZ
         =====
          WLYYM
         -RXQQV
          =====
           NRGNP
          -NJWWP
           =====
            GTLJ

base: 16
letters: GHJLMNPQRTUVWXYZ
difficulty: medium