????????
      +---------
GGETP | TPPTQHUT
       -TTXJH
        =====
         ENFTH
        -GGETP
         =====
          LTMPU
         -ULEJJ
          =====
           XFLHT
          -XXUNF
           =====
           ?????

base: 13
letters: EFGHJLMNPQTUX
difficulty: hard