QPWG
      +---------
WRYGR | YVTVUZRY
       -WRYGR
        =====
        GRNWLZ
       -GNVUWR
        ======
         HRNMMR
        -HHZZZX
         ======
          NHPPVY
         -QTXTQM
          ======
           UZVYH

base: 16
letters: GHJLMNPQRTUVWXYZ
difficulty: hard
missing: J