????????
      +---------
TGJPP | PRWRWGLW
       -NXNUU
        =====
         NHRTG
        -TGJPP
         =====
         TJPJNL
        -THXJUQ
         ======
           HUNXW
          -HJTPN
           =====
           ?????

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