ducts udcts dcuts cduts ucdts cudts dutcs udtcs dtucs tducs utdcs tudcs dctus cdtus dtcus tdcus ctdus tcdus uctds cutds utcds tucds ctuds tcuds ducst udcst dcust cdust ucdst cudst dusct udsct dsuct sduct usdct sudct dcsut cdsut dscut sdcut csdut scdut ucsdt cusdt uscdt sucdt csudt scudt dutsc udtsc dtusc tdusc utdsc tudsc dustc udstc dsutc sdutc usdtc sudtc dtsuc tdsuc dstuc sdtuc tsduc stduc utsdc tusdc ustdc sutdc tsudc studc dctsu cdtsu dtcsu tdcsu ctdsu tcdsu dcstu cdstu dsctu sdctu csdtu scdtu dtscu tdscu dstcu sdtcu tsdcu stdcu ctsdu tcsdu cstdu sctdu tscdu stcdu uctsd cutsd utcsd tucsd ctusd tcusd ucstd custd usctd suctd csutd scutd utscd tuscd ustcd sutcd tsucd stucd ctsud tcsud cstud sctud tscud stcud
Note: these 'words' (valid or invalid) are all the permutations of the word ducts. These words are obtained by scrambling the letters in ducts.