perks eprks preks rpeks erpks repks pekrs epkrs pkers kpers ekprs keprs prkes rpkes pkres kpres rkpes krpes erkps rekps ekrps kerps rkeps kreps persk eprsk presk rpesk erpsk repsk pesrk epsrk pserk sperk esprk seprk prsek rpsek psrek sprek rspek srpek erspk respk esrpk serpk rsepk srepk peksr epksr pkesr kpesr ekpsr kepsr peskr epskr psekr spekr espkr sepkr pkser kpser psker spker ksper skper ekspr kespr eskpr sekpr ksepr skepr prkse rpkse pkrse kprse rkpse krpse prske rpske psrke sprke rspke srpke pksre kpsre pskre spkre kspre skpre rkspe krspe rskpe srkpe ksrpe skrpe erksp reksp ekrsp kersp rkesp kresp erskp reskp esrkp serkp rsekp srekp eksrp kesrp eskrp sekrp kserp skerp rksep krsep rskep srkep ksrep skrep
Note: these 'words' (valid or invalid) are all the permutations of the word perks. These words are obtained by scrambling the letters in perks.