pirls iprls prils rpils irpls ripls pilrs iplrs plirs lpirs ilprs liprs prlis rplis plris lpris rlpis lrpis irlps rilps ilrps lirps rlips lrips pirsl iprsl prisl rpisl irpsl ripsl pisrl ipsrl psirl spirl isprl siprl prsil rpsil psril spril rspil srpil irspl rispl isrpl sirpl rsipl sripl pilsr iplsr plisr lpisr ilpsr lipsr pislr ipslr psilr spilr isplr siplr plsir lpsir pslir splir lspir slpir ilspr lispr islpr silpr lsipr slipr prlsi rplsi plrsi lprsi rlpsi lrpsi prsli rpsli psrli sprli rspli srpli plsri lpsri pslri splri lspri slpri rlspi lrspi rslpi srlpi lsrpi slrpi irlsp rilsp ilrsp lirsp rlisp lrisp irslp rislp isrlp sirlp rsilp srilp ilsrp lisrp islrp silrp lsirp slirp rlsip lrsip rslip srlip lsrip slrip
Note: these 'words' (valid or invalid) are all the permutations of the word pirls. These words are obtained by scrambling the letters in pirls.