sills islls slils lsils ilsls lisls sills islls slils lsils ilsls lisls sllis lslis sllis lslis llsis llsis illss lilss illss lilss lliss lliss silsl islsl slisl lsisl ilssl lissl sisll issll ssill ssill issll sisll slsil lssil sslil sslil lssil slsil ilssl lissl islsl silsl lsisl slisl silsl islsl slisl lsisl ilssl lissl sisll issll ssill ssill issll sisll slsil lssil sslil sslil lssil slsil ilssl lissl islsl silsl lsisl slisl sllsi lslsi sllsi lslsi llssi llssi slsli lssli sslli sslli lssli slsli slsli lssli sslli sslli lssli slsli llssi llssi lslsi sllsi lslsi sllsi illss lilss illss lilss lliss lliss ilsls lisls islls sills lsils slils ilsls lisls islls sills lsils slils llsis llsis lslis sllis lslis sllis
Note: these 'words' (valid or invalid) are all the permutations of the word sills. These words are obtained by scrambling the letters in sills.