ktnc tknc kntc nktc tnkc ntkc ktcn tkcn kctn cktn tckn ctkn knct nkct kcnt cknt nckt cnkt tnck ntck tcnk ctnk nctk cntk
Note: these 'words' (valid or invalid) are all the permutations of the word ktnc. These words are obtained by scrambling the letters in ktnc.