XTYM
    +-------
WPU | NMPJQX
     -FHM
      ===
      WWWJ
     -WRFN
      ====
        HQQ
       -TJH
        ===
        WNNX
       -WNQX
        ====
          YR

base: 13
letters: FHJMNPQRTUWXY
difficulty: medium
missing: Y