JQW
      +---------
NLYRE | MXWQNULP
       -EFLPXN
        ======
         XMQEQL
        -XLFRXU
         ======
          WQRWQP
         - NLYRE
          ======
           LXMLL

base: 13
letters: EFJLMNPQRUWXY
difficulty: medium
restrictions: no multiplication