cauda acuda cuada ucada aucda uacda cadua acdua cdaua dcaua adcua dacua cudaa ucdaa cduaa dcuaa udcaa ducaa audca uadca aduca dauca udaca duaca cauad acuad cuaad ucaad aucad uacad caaud acaud caaud acaud aacud aacud cuaad ucaad cauad acuad uacad aucad auacd uaacd aaucd aaucd uaacd auacd cadau acdau cdaau dcaau adcau dacau caadu acadu caadu acadu aacdu aacdu cdaau dcaau cadau acdau dacau adcau adacu daacu aadcu aadcu daacu adacu cudaa ucdaa cduaa dcuaa udcaa ducaa cuada ucada cauda acuda uacda aucda cdaua dcaua cadua acdua dacua adcua udaca duaca uadca audca dauca aduca audac uadac aduac dauac udaac duaac auadc uaadc aaudc aaudc uaadc auadc adauc daauc aaduc aaduc daauc adauc udaac duaac uadac audac dauac aduac
Note: these 'words' (valid or invalid) are all the permutations of the word cauda. These words are obtained by scrambling the letters in cauda.