furth ufrth fruth rfuth urfth rufth futrh uftrh fturh tfurh utfrh tufrh frtuh rftuh ftruh tfruh rtfuh trfuh urtfh rutfh utrfh turfh rtufh trufh furht ufrht fruht rfuht urfht rufht fuhrt ufhrt fhurt hfurt uhfrt hufrt frhut rfhut fhrut hfrut rhfut hrfut urhft ruhft uhrft hurft rhuft hruft futhr ufthr ftuhr tfuhr utfhr tufhr fuhtr ufhtr fhutr hfutr uhftr huftr fthur tfhur fhtur hftur thfur htfur uthfr tuhfr uhtfr hutfr thufr htufr frthu rfthu ftrhu tfrhu rtfhu trfhu frhtu rfhtu fhrtu hfrtu rhftu hrftu fthru tfhru fhtru hftru thfru htfru rthfu trhfu rhtfu hrtfu thrfu htrfu urthf ruthf utrhf turhf rtuhf truhf urhtf ruhtf uhrtf hurtf rhutf hrutf uthrf tuhrf uhtrf hutrf thurf hturf rthuf trhuf rhtuf hrtuf thruf htruf
Note: these 'words' (valid or invalid) are all the permutations of the word furth. These words are obtained by scrambling the letters in furth.