HEW
      +---------
EWWQE | ENXRPQPF
       -LYHLLP
        ======
         XXLYEP
        -XUXFXY
         ======
          WQLNEF
         -PFXXPF
          ======
           UQTXQ

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