nupf unpf npuf pnuf upnf punf nufp unfp nfup fnup ufnp funp npfu pnfu nfpu fnpu pfnu fpnu upfn pufn ufpn fupn pfun fpun
Note: these 'words' (valid or invalid) are all the permutations of the word nupf. These words are obtained by scrambling the letters in nupf.