MTTF
      +---------
MYLER | RUYLGFYR
       -MYLER
        =====
        MYLNHF
       -MEUGWL
        ======
         MYGWMY
        -MEUGWL
         ======
          MEJNLR
         -MNYFRY
          ======
           MHEEW

base: 13
letters: EFGHJLMNRTUWY
difficulty: medium
missing: T