LQRR
      +---------
VLYUX | PYHHPTQU
       -VLYUX
        =====
        MJXMQT
       -MULNQN
        ======
         MTXWHQ
        -MYZGXM
         ======
          MRLYJU
         -MYZGXM
          ======
           ZGPJX

base: 16
letters: GHJLMNPQRTUVWXYZ
difficulty: medium