XLHY
    +-------
LYW | NJULTF
     -GTQ
      ===
       FNL
      -WMP
       ===
       JYLT
      -JHUP
       ====
        XQTF
       -XXFP
        ====
         XGF

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