PWFX
    +-------
GXG | XGHFUJ
     -PWP
      ===
       FPF
      -RMW
       ===
        QPU
       -JYF
        ===
         HHJ
        -XJX
         ===
          FW

base: 13
letters: EFGHJMPQRUWXY
difficulty: medium
missing: E