?????????
      +----------
FTHJP | GRTTJGWRN
       -FTHJP
        =====
        FPNHYG
       -FRHHJR
        ======
          YWRFW
         -FTHJP
          =====
          JWGURR
         -QYLLHJ
          ======
           NWJGJN
          -JHLUQN
           ======
           ??????

base: 13
letters: FGHJLNPQRTUWY
difficulty: intermediate