????????
      +---------
PNGXE | MEYXCEGC
       -MQXQC
        =====
         PMQJE
        -PNGXE
         =====
          HXPJG
         -GXEEJ
          =====
           MQCGC
          -YPNGE
           =====
           ?????

base: 12
letters: CEGHJMNPQWXY
missing: W
difficulty: medium