????????
      +---------
PXFLF | EEFEPFFF
       -PXFLF
        =====
         NTPLF
        -YLXWX
         =====
          YCYCF
         -YLXWX
          =====
           MFECF
          -PXFLF
           =====
           ?????

base: 11
letters: CEFLMNPTWXY
difficulty: intermediate