VZP
      +--------
VWLQX | PMHTNPT
       -QYNNL
        =====
        WLYJLP
       -WHXMNR
        ======
          LWYGT
         -UNZPR
          =====
          WNXWH

base: 16
letters: GHJLMNPQRTUVWXYZ
difficulty: hard