YRX
      +--------
FYLRH | PWYYUWU
       -PXFRJ
        =====
         NNGRW
        -XMQRW
         =====
          YQTTU
         -YXWQP
          =====
           GGNL

base: 15
letters: FGHJLMNPQRTUWXY
difficulty: hard