ntcwa tncwa nctwa cntwa tcnwa ctnwa ntwca tnwca nwtca wntca twnca wtnca ncwta cnwta nwcta wncta cwnta wcnta tcwna ctwna twcna wtcna cwtna wctna ntcaw tncaw nctaw cntaw tcnaw ctnaw ntacw tnacw natcw antcw tancw atncw ncatw cnatw nactw anctw cantw acntw tcanw ctanw tacnw atcnw catnw actnw ntwac tnwac nwtac wntac twnac wtnac ntawc tnawc natwc antwc tanwc atnwc nwatc wnatc nawtc anwtc wantc awntc twanc wtanc tawnc atwnc watnc awtnc ncwat cnwat nwcat wncat cwnat wcnat ncawt cnawt nacwt ancwt canwt acnwt nwact wnact nawct anwct wanct awnct cwant wcant cawnt acwnt wacnt awcnt tcwan ctwan twcan wtcan cwtan wctan tcawn ctawn tacwn atcwn catwn actwn twacn wtacn tawcn atwcn watcn awtcn cwatn wcatn cawtn acwtn wactn awctn
Note: these 'words' (valid or invalid) are all the permutations of the word ntcwa. These words are obtained by scrambling the letters in ntcwa.