iltss litss itlss tilss ltiss tliss ilsts lists islts silts lsits slits itsls tisls istls sitls tsils stils ltsis tlsis lstis sltis tslis stlis iltss litss itlss tilss ltiss tliss ilsts lists islts silts lsits slits itsls tisls istls sitls tsils stils ltsis tlsis lstis sltis tslis stlis ilsst lisst islst silst lsist slist ilsst lisst islst silst lsist slist isslt sislt isslt sislt ssilt ssilt lssit slsit lssit slsit sslit sslit itssl tissl istsl sitsl tsisl stisl itssl tissl istsl sitsl tsisl stisl isstl sistl isstl sistl ssitl ssitl tssil stsil tssil stsil sstil sstil ltssi tlssi lstsi sltsi tslsi stlsi ltssi tlssi lstsi sltsi tslsi stlsi lssti slsti lssti slsti sslti sslti tssli stsli tssli stsli sstli sstli
Note: these 'words' (valid or invalid) are all the permutations of the word iltss. These words are obtained by scrambling the letters in iltss.