perns eprns prens rpens erpns repns penrs epnrs pners npers enprs neprs prnes rpnes pnres npres rnpes nrpes ernps renps enrps nerps rneps nreps persn eprsn presn rpesn erpsn repsn pesrn epsrn psern spern esprn seprn prsen rpsen psren spren rspen srpen erspn respn esrpn serpn rsepn srepn pensr epnsr pnesr npesr enpsr nepsr pesnr epsnr psenr spenr espnr sepnr pnser npser psner spner nsper snper enspr nespr esnpr senpr nsepr snepr prnse rpnse pnrse nprse rnpse nrpse prsne rpsne psrne sprne rspne srpne pnsre npsre psnre spnre nspre snpre rnspe nrspe rsnpe srnpe nsrpe snrpe ernsp rensp enrsp nersp rnesp nresp ersnp resnp esrnp sernp rsenp srenp ensrp nesrp esnrp senrp nserp snerp rnsep nrsep rsnep srnep nsrep snrep
Note: these 'words' (valid or invalid) are all the permutations of the word perns. These words are obtained by scrambling the letters in perns.