wudu uwdu wduu dwuu udwu duwu wuud uwud wuud uwud uuwd uuwd wduu dwuu wudu uwdu duwu udwu uduw duuw uudw uudw duuw uduw
Note: these 'words' (valid or invalid) are all the permutations of the word wudu. These words are obtained by scrambling the letters in wudu.