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