PMG
      +---------
UUXLH | PMERPFHX
       -LUFMPR
        ======
         MMFTWH
        -EUERGF
         ======
          GHRMWX
         -MURJFL
          ======
           HUJEH

base: 13
letters: EFGHJLMPRTUWX
difficulty: intermediate
restrictions: no multiplication