stlee tslee sltee lstee tlsee ltsee stele tsele setle estle tesle etsle slete lsete selte eslte leste elste tlese ltese telse etlse letse eltse stlee tslee sltee lstee tlsee ltsee stele tsele setle estle tesle etsle slete lsete selte eslte leste elste tlese ltese telse etlse letse eltse steel tseel setel estel tesel etsel steel tseel setel estel tesel etsel seetl esetl seetl esetl eestl eestl teesl etesl teesl etesl eetsl eetsl sleet lseet selet eslet leset elset sleet lseet selet eslet leset elset seelt eselt seelt eselt eeslt eeslt leest elest leest elest eelst eelst tlees ltees teles etles letes eltes tlees ltees teles etles letes eltes teels etels teels etels eetls eetls leets elets leets elets eelts eelts
Note: these 'words' (valid or invalid) are all the permutations of the word stlee. These words are obtained by scrambling the letters in stlee.