?????????
      +----------
WYHGN | XNXXCHXNH
       -WYHGN
        =====
        WWUHNH
       -WGGWYW
        ======
         WUUWUX
        -WGGWYW
         ======
          UGNXWN
         -UGGUWY
          ======
            NHGWH
           -YWCUC
            =====
            ?????

base: 8
letters: CGHNUWXY
difficulty: intermediate