LURH
      +---------
QUEQR | HQPNRREL
       -TGNTP
        =====
        LNFRUR
       -LPGHPN
        ======
         LTTWQE
        -LWRUWF
         ======
          QPHHHL
         -NFEGFJ
          ======
           QNHGN

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