HQJG
      +---------
PFTGF | XWFUWPFT
       -LJWJX
        =====
        PTYHQP
       -PWXHUU
        ======
         PXEWJF
        -PTTFWG
         ======
           HLYQT
          -UFUYJ
           =====
            TGHQ

base: 13
letters: EFGHJLPQTUWXY
difficulty: medium