RWG
      +--------
ZNGML | VUGNYXZ
       -ZNGML
        =====
        ZQJRNX
       -QGYJMH
        ======
         ZTRRWZ
        -ZVQGQW
         ======
          QGZTY

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