NPX
      +--------
JMTJP | WWXQHXM
       -JMTJP
        =====
        JNLPPX
       -QPYGNQ
        ======
         YPJFRM
        -YMJUHN
         ======
          RUFXG

base: 15
letters: FGHJLMNPQRTUWXY
difficulty: hard