ihstf histf ishtf sihtf hsitf shitf ihtsf hitsf ithsf tihsf htisf thisf isthf sithf itshf tishf stihf tsihf hstif shtif htsif thsif sthif tshif ihsft hisft ishft sihft hsift shift ihfst hifst ifhst fihst hfist fhist isfht sifht ifsht fisht sfiht fsiht hsfit shfit hfsit fhsit sfhit fshit ihtfs hitfs ithfs tihfs htifs thifs ihfts hifts ifhts fihts hfits fhits itfhs tifhs ifths fiths tfihs ftihs htfis thfis hftis fhtis tfhis fthis istfh sitfh itsfh tisfh stifh tsifh isfth sifth ifsth fisth sfith fsith itfsh tifsh iftsh fitsh tfish ftish stfih tsfih sftih fstih tfsih ftsih hstfi shtfi htsfi thsfi sthfi tshfi hsfti shfti hfsti fhsti sfhti fshti htfsi thfsi hftsi fhtsi tfhsi fthsi stfhi tsfhi sfthi fsthi tfshi ftshi
Note: these 'words' (valid or invalid) are all the permutations of the word ihstf. These words are obtained by scrambling the letters in ihstf.