unban nuban ubnan bunan nbuan bnuan unabn nuabn uanbn aunbn naubn anubn ubann buann uabnn aubnn baunn abunn nbaun bnaun nabun anbun banun abnun unbna nubna ubnna bunna nbuna bnuna unnba nunba unnba nunba nnuba nnuba ubnna bunna unbna nubna bnuna nbuna nbnua bnnua nnbua nnbua bnnua nbnua unanb nuanb uannb aunnb naunb anunb unnab nunab unnab nunab nnuab nnuab uannb aunnb unanb nuanb anunb naunb nanub annub nnaub nnaub annub nanub ubann buann uabnn aubnn baunn abunn ubnan bunan unban nuban bnuan nbuan uanbn aunbn unabn nuabn anubn naubn banun abnun bnaun nbaun anbun nabun nbanu bnanu nabnu anbnu bannu abnnu nbnau bnnau nnbau nnbau bnnau nbnau nanbu annbu nnabu nnabu annbu nanbu bannu abnnu bnanu nbanu anbnu nabnu
Note: these 'words' (valid or invalid) are all the permutations of the word unban. These words are obtained by scrambling the letters in unban.