fifer iffer ffier ffier iffer fifer fiefr ifefr feifr efifr ieffr eiffr ffeir ffeir fefir effir fefir effir ifefr fiefr ieffr eiffr feifr efifr fifre iffre ffire ffire iffre fifre firfe ifrfe frife rfife irffe riffe ffrie ffrie frfie rffie frfie rffie ifrfe firfe irffe riffe frife rfife fierf iferf feirf efirf iefrf eifrf firef ifref frief rfief irfef rifef ferif efrif freif rfeif erfif refif ierff eirff ireff rieff eriff reiff fferi fferi fefri effri fefri effri ffrei ffrei frfei rffei frfei rffei ferfi efrfi frefi rfefi erffi reffi ferfi efrfi frefi rfefi erffi reffi iferf fierf iefrf eifrf feirf efirf ifref firef irfef rifef frief rfief ierff eirff ireff rieff eriff reiff ferif efrif freif rfeif erfif refif
Note: these 'words' (valid or invalid) are all the permutations of the word fifer. These words are obtained by scrambling the letters in fifer.