PQG
      +--------
WHUYR | QMTYYTQ
       -YJYHU
        =====
        LYHPJT
       -LMRGUX
        ======
          TJGTQ
         -THWFX
          =====
           TWJQ

base: 15
letters: FGHJLMNPQRTUWXY
difficulty: hard
missing: N