pirns iprns prins rpins irpns ripns pinrs ipnrs pnirs npirs inprs niprs prnis rpnis pnris npris rnpis nrpis irnps rinps inrps nirps rnips nrips pirsn iprsn prisn rpisn irpsn ripsn pisrn ipsrn psirn spirn isprn siprn prsin rpsin psrin sprin rspin srpin irspn rispn isrpn sirpn rsipn sripn pinsr ipnsr pnisr npisr inpsr nipsr pisnr ipsnr psinr spinr ispnr sipnr pnsir npsir psnir spnir nspir snpir inspr nispr isnpr sinpr nsipr snipr prnsi rpnsi pnrsi nprsi rnpsi nrpsi prsni rpsni psrni sprni rspni srpni pnsri npsri psnri spnri nspri snpri rnspi nrspi rsnpi srnpi nsrpi snrpi irnsp rinsp inrsp nirsp rnisp nrisp irsnp risnp isrnp sirnp rsinp srinp insrp nisrp isnrp sinrp nsirp snirp rnsip nrsip rsnip srnip nsrip snrip
Note: these 'words' (valid or invalid) are all the permutations of the word pirns. These words are obtained by scrambling the letters in pirns.