tirls itrls trils rtils irtls ritls tilrs itlrs tlirs ltirs iltrs litrs trlis rtlis tlris ltris rltis lrtis irlts rilts ilrts lirts rlits lrits tirsl itrsl trisl rtisl irtsl ritsl tisrl itsrl tsirl stirl istrl sitrl trsil rtsil tsril stril rstil srtil irstl ristl isrtl sirtl rsitl sritl tilsr itlsr tlisr ltisr iltsr litsr tislr itslr tsilr stilr istlr sitlr tlsir ltsir tslir stlir lstir sltir ilstr listr isltr siltr lsitr slitr trlsi rtlsi tlrsi ltrsi rltsi lrtsi trsli rtsli tsrli strli rstli srtli tlsri ltsri tslri stlri lstri sltri rlsti lrsti rslti srlti lsrti slrti irlst rilst ilrst lirst rlist lrist irslt rislt isrlt sirlt rsilt srilt ilsrt lisrt islrt silrt lsirt slirt rlsit lrsit rslit srlit lsrit slrit
Note: these 'words' (valid or invalid) are all the permutations of the word tirls. These words are obtained by scrambling the letters in tirls.