doubt odubt duobt udobt oudbt uodbt dobut odbut dbout bdout obdut bodut dubot udbot dbuot bduot ubdot budot oubdt uobdt obudt boudt ubodt buodt doutb odutb duotb udotb oudtb uodtb dotub odtub dtoub tdoub otdub todub dutob udtob dtuob tduob utdob tudob outdb uotdb otudb toudb utodb tuodb dobtu odbtu dbotu bdotu obdtu bodtu dotbu odtbu dtobu tdobu otdbu todbu dbtou bdtou dtbou tdbou btdou tbdou obtdu botdu otbdu tobdu btodu tbodu dubto udbto dbuto bduto ubdto budto dutbo udtbo dtubo tdubo utdbo tudbo dbtuo bdtuo dtbuo tdbuo btduo tbduo ubtdo butdo utbdo tubdo btudo tbudo oubtd uobtd obutd boutd ubotd buotd outbd uotbd otubd toubd utobd tuobd obtud botud otbud tobud btoud tboud ubtod butod utbod tubod btuod tbuod
Note: these 'words' (valid or invalid) are all the permutations of the word doubt. These words are obtained by scrambling the letters in doubt.