xsru sxru xrsu rxsu srxu rsxu xsur sxur xusr uxsr suxr usxr xrus rxus xurs uxrs ruxs urxs srux rsux surx usrx rusx ursx
Note: these 'words' (valid or invalid) are all the permutations of the word xsru. These words are obtained by scrambling the letters in xsru.