prong rpong porng oprng ropng orpng prnog rpnog pnrog nprog rnpog nrpog ponrg opnrg pnorg nporg onprg noprg ronpg ornpg rnopg nropg onrpg norpg progn rpogn porgn oprgn ropgn orpgn prgon rpgon pgron gpron rgpon grpon pogrn opgrn pgorn gporn ogprn goprn rogpn orgpn rgopn gropn ogrpn gorpn prngo rpngo pnrgo nprgo rnpgo nrpgo prgno rpgno pgrno gprno rgpno grpno pngro npgro pgnro gpnro ngpro gnpro rngpo nrgpo rgnpo grnpo ngrpo gnrpo pongr opngr pnogr npogr onpgr nopgr pognr opgnr pgonr gponr ogpnr gopnr pngor npgor pgnor gpnor ngpor gnpor ongpr nogpr ognpr gonpr ngopr gnopr rongp orngp rnogp nrogp onrgp norgp rognp orgnp rgonp gronp ogrnp gornp rngop nrgop rgnop grnop ngrop gnrop ongrp nogrp ognrp gonrp ngorp gnorp
Note: these 'words' (valid or invalid) are all the permutations of the word prong. These words are obtained by scrambling the letters in prong.