kack akck kcak ckak ackk cakk kakc akkc kkac kkac akkc kakc kcka ckka kkca kkca ckka kcka ackk cakk akck kack ckak kcak
Note: these 'words' (valid or invalid) are all the permutations of the word kack. These words are obtained by scrambling the letters in kack.