????????
      ----------
YLUGF ) UHWMWRUM
       -YLUGF
        =====
        FLYWJR
       -FQPYQN
        ======
         NMMJUU
        -NXGQQR
         ======
          LWJYWM
         -LHWJGP
          ======
          ??????

base: 15
symbols: FGHJLMNPQRTUWXY
difficulty: medium
missing: T