QPRY
      +---------
EPGEN | HWFGHENW
       -EPGEN
        =====
        RGTWQE
       -RFGRGN
        ======
         QPNGWN
        -QRHQYP
         ======
          QWFNPW
         -QTQEWM
          ======
           QPMFW

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