????????
      +---------
YFFFX | YNFGWNNY
       -YFFFX
        =====
         RXLFN
        -YFFFX
         =====
         YUJXPN
        -YHUUQR
         ======
           LFRLY
          -FPXJL
           =====
           ?????

base: 13
letters: FGHJLNPQRUWXY
difficulty: hard