chack hcack cahck achck hacck ahcck chcak hccak cchak cchak hccak chcak cachk acchk ccahk ccahk acchk cachk hacck ahcck hcack chack achck cahck chakc hcakc cahkc achkc hackc ahckc chkac hckac ckhac kchac hkcac khcac cakhc ackhc ckahc kcahc akchc kachc hakcc ahkcc hkacc khacc akhcc kahcc chcka hccka cchka cchka hccka chcka chkca hckca ckhca kchca hkcca khcca cckha cckha ckcha kccha ckcha kccha hckca chkca hkcca khcca ckhca kchca cackh acckh ccakh ccakh acckh cackh cakch ackch ckach kcach akcch kacch cckah cckah ckcah kccah ckcah kccah ackch cakch akcch kacch ckach kcach hackc ahckc hcakc chakc achkc cahkc hakcc ahkcc hkacc khacc akhcc kahcc hckac chkac hkcac khcac ckhac kchac ackhc cakhc akchc kachc ckahc kcahc
Note: these 'words' (valid or invalid) are all the permutations of the word chack. These words are obtained by scrambling the letters in chack.