whaft hwaft wahft awhft hawft ahwft whfat hwfat wfhat fwhat hfwat fhwat wafht awfht wfaht fwaht afwht fawht hafwt ahfwt hfawt fhawt afhwt fahwt whatf hwatf wahtf awhtf hawtf ahwtf whtaf hwtaf wthaf twhaf htwaf thwaf wathf awthf wtahf twahf atwhf tawhf hatwf ahtwf htawf thawf athwf tahwf whfta hwfta wfhta fwhta hfwta fhwta whtfa hwtfa wthfa twhfa htwfa thwfa wftha fwtha wtfha twfha ftwha tfwha hftwa fhtwa htfwa thfwa fthwa tfhwa wafth awfth wfath fwath afwth fawth watfh awtfh wtafh twafh atwfh tawfh wftah fwtah wtfah twfah ftwah tfwah aftwh fatwh atfwh tafwh ftawh tfawh haftw ahftw hfatw fhatw afhtw fahtw hatfw ahtfw htafw thafw athfw tahfw hftaw fhtaw htfaw thfaw fthaw tfhaw afthw fathw atfhw tafhw ftahw tfahw
Note: these 'words' (valid or invalid) are all the permutations of the word whaft. These words are obtained by scrambling the letters in whaft.