TNQ
      +--------
XQHJF | LPYWQTH
       -WULMN
        =====
        XLXFXT
       -XTQHUF
        ======
         XLNGPH
        -XLULGN
         ======
           TWLJ

base: 15
letters: FGHJLMNPQRTUWXY
difficulty: challenging
missing: R