chdca hcdca cdhca dchca hdcca dhcca chcda hccda cchda cchda hccda chcda cdcha dccha ccdha ccdha dccha cdcha hdcca dhcca hcdca chdca dchca cdhca chdac hcdac cdhac dchac hdcac dhcac chadc hcadc cahdc achdc hacdc ahcdc cdahc dcahc cadhc acdhc dachc adchc hdacc dhacc hadcc ahdcc dahcc adhcc chcad hccad cchad cchad hccad chcad chacd hcacd cahcd achcd haccd ahccd ccahd ccahd cachd acchd cachd acchd hcacd chacd haccd ahccd cahcd achcd cdcah dccah ccdah ccdah dccah cdcah cdach dcach cadch acdch dacch adcch ccadh ccadh cacdh accdh cacdh accdh dcach cdach dacch adcch cadch acdch hdcac dhcac hcdac chdac dchac cdhac hdacc dhacc hadcc ahdcc dahcc adhcc hcadc chadc hacdc ahcdc cahdc achdc dcahc cdahc dachc adchc cadhc acdhc
Note: these 'words' (valid or invalid) are all the permutations of the word chdca. These words are obtained by scrambling the letters in chdca.