JRPW
      +---------
PXGHU | TLMJQXGT
       -TPRRR
        =====
         HGLNX
        -HRMQJ
         =====
          PTXUG
         -PXGHU
          =====
           MNWTT
          -WLYRL
           =====
            LLPN

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