????????
      ----------
RHGQV ) HRPYRVTY
       -RHGQV
        =====
        NVUYPV
       -NYTNQN
        ======
         JPGGXT
        -JTRRUY
         ======
          JMZVYY
         -JLVYUU
          ======
          ??????

base: 16
symbols: GHJLMNPQRTUVWXYZ
difficulty: hard
missing: W