siltd isltd slitd lsitd ilstd listd sitld istld stild tsild itsld tisld sltid lstid stlid tslid ltsid tlsid iltsd litsd itlsd tilsd ltisd tlisd sildt isldt slidt lsidt ilsdt lisdt sidlt isdlt sdilt dsilt idslt dislt sldit lsdit sdlit dslit ldsit dlsit ildst lidst idlst dilst ldist dlist sitdl istdl stidl tsidl itsdl tisdl sidtl isdtl sditl dsitl idstl distl stdil tsdil sdtil dstil tdsil dtsil itdsl tidsl idtsl ditsl tdisl dtisl sltdi lstdi stldi tsldi ltsdi tlsdi sldti lsdti sdlti dslti ldsti dlsti stdli tsdli sdtli dstli tdsli dtsli ltdsi tldsi ldtsi dltsi tdlsi dtlsi iltds litds itlds tilds ltids tlids ildts lidts idlts dilts ldits dlits itdls tidls idtls ditls tdils dtils ltdis tldis ldtis dltis tdlis dtlis
Note: these 'words' (valid or invalid) are all the permutations of the word siltd. These words are obtained by scrambling the letters in siltd.