Universal partial word verifier

Alphabet: {}
(Symbols other than the digits 0–9 and the letters A–Z and a–z will be ignored. In particular, you can use commas and whitespace as symbol separators if you like, but they are not required.)

n =
(The length of the words that should be covered by the universal partial word.)

Partial word to check for universality:
(All non-whitespace symbols not in the alphabet will be treated as the wildcard symbol ◇.)