LJP
      +--------
YGGXW | FRJNLLR
       -YGGXW
        =====
        PRTJGL
       -PPGQHG
        ======
         LTHMWR
        -LRGNNY
         ======
          WHWXG

base: 15
letters: FGHJLMNPQRTUWXY
difficulty: hard
missing: U