????????
      +---------
UQWLH | HMGUFXTG
       -WURPY
        =====
        UPNFHX
       -UHGPUY
        ======
          GLWUT
         -NPJXY
          =====
           FMTFG
          -MHQTR
           =====
           ?????

base: 15
letters: FGHJLMNPQRTUWXY
difficulty: hard