MXP
      +---------
HJEJX | XJLEGRRF
       -XEGWXX
        ======
         XETHHR
        -GRMHJT
         ======
          HGTFRF
         -JHXGLX
          ======
           XGMMM

base: 12
letters: EFGHJLMPRTWX
difficulty: medium
restrictions: no multiplication