????????
      +---------
MQGRQ | PMNRPHGM
       -MQGRQ
        =====
         QMXHH
        -RGMLP
         =====
          EEHRG
         -UEERU
          =====
           XFXRM
          -XRPLW
           =====
           ?????

base: 13
letters: EFGHLMNPQRUWX
difficulty: medium