prank rpank parnk aprnk rapnk arpnk prnak rpnak pnrak nprak rnpak nrpak panrk apnrk pnark npark anprk naprk ranpk arnpk rnapk nrapk anrpk narpk prakn rpakn parkn aprkn rapkn arpkn prkan rpkan pkran kpran rkpan krpan pakrn apkrn pkarn kparn akprn kaprn rakpn arkpn rkapn krapn akrpn karpn prnka rpnka pnrka nprka rnpka nrpka prkna rpkna pkrna kprna rkpna krpna pnkra npkra pknra kpnra nkpra knpra rnkpa nrkpa rknpa krnpa nkrpa knrpa pankr apnkr pnakr npakr anpkr napkr paknr apknr pkanr kpanr akpnr kapnr pnkar npkar pknar kpnar nkpar knpar ankpr nakpr aknpr kanpr nkapr knapr rankp arnkp rnakp nrakp anrkp narkp raknp arknp rkanp kranp akrnp karnp rnkap nrkap rknap krnap nkrap knrap ankrp nakrp aknrp kanrp nkarp knarp
Note: these 'words' (valid or invalid) are all the permutations of the word prank. These words are obtained by scrambling the letters in prank.