????????
      +---------
MWXFG | MRNWRRTM
       -MWXFG
        =====
         MJTMR
        -MWXFG
         =====
          RQGMT
         -GNRXQ
          =====
          MPJTJM
         -ULMGNT
          ======
          ??????

base: 13
letters: FGJLMNPQRTUWX
difficulty: hard
hints: G << T, P << M