cctk cctk ctck tcck ctck tcck cckt cckt ckct kcct ckct kcct ctkc tckc cktc kctc tkcc ktcc ctkc tckc cktc kctc tkcc ktcc
Note: these 'words' (valid or invalid) are all the permutations of the word cctk. These words are obtained by scrambling the letters in cctk.