?????????
      +----------
GEFTE | FXXLLUEMW
       -GEFTE
        =====
        RPEFGU
       -RNXFMG
        ======
         NEXPJE
        -RTEUUL
         ======
          RPHULM
         -RNXFMG
          ======
           NHFXHW
          -RTEUUL
           ======
           ??????

base: 14
letters: EFGHJLMNPRTUWX
difficulty: challenging