treck rteck terck etrck retck ertck trcek rtcek tcrek ctrek rctek crtek tecrk etcrk tcerk cterk ectrk cetrk rectk erctk rcetk cretk ecrtk certk trekc rtekc terkc etrkc retkc ertkc trkec rtkec tkrec ktrec rktec krtec tekrc etkrc tkerc kterc ektrc ketrc rektc erktc rketc kretc ekrtc kertc trcke rtcke tcrke ctrke rctke crtke trkce rtkce tkrce ktrce rktce krtce tckre ctkre tkcre ktcre cktre kctre rckte crkte rkcte krcte ckrte kcrte teckr etckr tcekr ctekr ectkr cetkr tekcr etkcr tkecr ktecr ektcr ketcr tcker ctker tkcer ktcer ckter kcter ecktr cektr ekctr kectr cketr kcetr reckt erckt rcekt crekt ecrkt cerkt rekct erkct rkect krect ekrct kerct rcket crket rkcet krcet ckret kcret eckrt cekrt ekcrt kecrt ckert kcert
Note: these 'words' (valid or invalid) are all the permutations of the word treck. These words are obtained by scrambling the letters in treck.