skyb ksyb sykb yskb kysb yksb skby ksby sbky bsky kbsy bksy sybk ysbk sbyk bsyk ybsk bysk kybs ykbs kbys bkys ybks byks
Note: these 'words' (valid or invalid) are all the permutations of the word skyb. These words are obtained by scrambling the letters in skyb.