????????
      +---------
TYYER | YYUHTTTL
       -TYYER
        =====
         WRENT
        -TYYER
         =====
         FHFYNT
        -FEMJQH
         ======
           RUQUL
          -TYYER
           =====
          ??????

base: 13
letters: EFHJLMNQRTUWY
difficulty: challenging