tetsr ettsr ttesr ttesr ettsr tetsr testr etstr tsetr stetr esttr settr ttser ttser tster stter tster stter etstr testr esttr settr tsetr stetr tetrs ettrs tters tters ettrs tetrs terts etrts trets rtets ertts retts ttres ttres trtes rttes trtes rttes etrts terts ertts retts trets rtets tesrt etsrt tsert stert estrt setrt terst etrst trest rtest ertst retst tsret stret trset rtset srtet rstet esrtt sertt erstt restt srett rsett ttsre ttsre tstre sttre tstre sttre ttrse ttrse trtse rttse trtse rttse tsrte strte trste rtste srtte rstte tsrte strte trste rtste srtte rstte etsrt tesrt estrt setrt tsert stert etrst terst ertst retst trest rtest esrtt sertt erstt restt srett rsett tsret stret trset rtset srtet rstet
Note: these 'words' (valid or invalid) are all the permutations of the word tetsr. These words are obtained by scrambling the letters in tetsr.