MQNQ
      +---------
QHGUR | YGYLTHYN
       -LVZPW
        =====
         LZPTH
        -VTXHR
         =====
         HNYMJY
        -HNQGLR
         ======
           VPPGN
          -VTXHR
           =====
            TYQT

base: 16
letters: GHJLMNPQRTUVWXYZ
difficulty: hard