????????
      +---------
PPHWX | MJHRRJPH
       - GLRPW
        ======
         MHLGGP
        -MRPJXF
         ======
          RTGWHH
         -RTHGMG
          ======
          ??????

base: 12
letters: FGHJLMPQRTWX
missing: Q
difficulty: medium