XWJ
      +--------
TMYWR | GNRGNLM
       -TMYWR
        =====
         PXJYL
        -UQPUZ
         =====
         TQPJGM
        -XVWYYV
         ======
          XYGYZ

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