tehrs ethrs thers hters ehtrs hetrs terhs etrhs trehs rtehs erths reths thres htres trhes rthes hrtes rhtes ehrts herts erhts rehts hrets rhets tehsr ethsr thesr htesr ehtsr hetsr teshr etshr tsehr stehr esthr sethr thser htser tsher sther hster shter ehstr hestr eshtr sehtr hsetr shetr tersh etrsh tresh rtesh ertsh retsh tesrh etsrh tserh sterh estrh setrh trseh rtseh tsreh streh rsteh srteh ersth resth esrth serth rseth sreth thrse htrse trhse rthse hrtse rhtse thsre htsre tshre sthre hstre shtre trshe rtshe tsrhe strhe rsthe srthe hrste rhste hsrte shrte rshte srhte ehrst herst erhst rehst hrest rhest ehsrt hesrt eshrt sehrt hsert shert ersht resht esrht serht rseht sreht hrset rhset hsret shret rshet srhet
Note: these 'words' (valid or invalid) are all the permutations of the word tehrs. These words are obtained by scrambling the letters in tehrs.