prnex rpnex pnrex nprex rnpex nrpex prenx rpenx pernx eprnx repnx erpnx pnerx nperx penrx epnrx neprx enprx rnepx nrepx renpx ernpx nerpx enrpx prnxe rpnxe pnrxe nprxe rnpxe nrpxe prxne rpxne pxrne xprne rxpne xrpne pnxre npxre pxnre xpnre nxpre xnpre rnxpe nrxpe rxnpe xrnpe nxrpe xnrpe prexn rpexn perxn eprxn repxn erpxn prxen rpxen pxren xpren rxpen xrpen pexrn epxrn pxern xpern exprn xeprn rexpn erxpn rxepn xrepn exrpn xerpn pnexr npexr penxr epnxr nepxr enpxr pnxer npxer pxner xpner nxper xnper pexnr epxnr pxenr xpenr expnr xepnr nexpr enxpr nxepr xnepr exnpr xenpr rnexp nrexp renxp ernxp nerxp enrxp rnxep nrxep rxnep xrnep nxrep xnrep rexnp erxnp rxenp xrenp exrnp xernp nexrp enxrp nxerp xnerp exnrp xenrp
Note: these 'words' (valid or invalid) are all the permutations of the word prnex. These words are obtained by scrambling the letters in prnex.