????????
      +---------
HMRUU | JLGQRWYL
       -HMRUU
        =====
        QGGWTW
       -QFGRGT
        ======
         NRWYTY
        -NHYYLQ
         ======
          TLRUUL
         -TGXYYH
          ======
          ??????

base: 15
letters: FGHJLMNPQRTUWXY
difficulty: hard
missing: P