prein rpein perin eprin repin erpin prien rpien piren ipren ripen irpen peirn epirn piern ipern eiprn ieprn reipn eripn riepn irepn eirpn ierpn preni rpeni perni eprni repni erpni prnei rpnei pnrei nprei rnpei nrpei penri epnri pneri nperi enpri nepri renpi ernpi rnepi nrepi enrpi nerpi prine rpine pirne iprne ripne irpne prnie rpnie pnrie nprie rnpie nrpie pinre ipnre pnire npire inpre nipre rinpe irnpe rnipe nripe inrpe nirpe peinr epinr pienr ipenr eipnr iepnr penir epnir pneir npeir enpir nepir piner ipner pnier npier inper niper einpr ienpr enipr neipr inepr niepr reinp erinp rienp irenp eirnp iernp renip ernip rneip nreip enrip nerip rinep irnep rniep nriep inrep nirep einrp ienrp enirp neirp inerp nierp
Note: these 'words' (valid or invalid) are all the permutations of the word prein. These words are obtained by scrambling the letters in prein.