fruod rfuod furod ufrod rufod urfod froud rfoud forud ofrud rofud orfud fuord uford fourd ofurd uofrd oufrd ruofd urofd roufd orufd uorfd ourfd frudo rfudo furdo ufrdo rufdo urfdo frduo rfduo fdruo dfruo rdfuo drfuo fudro ufdro fduro dfuro udfro dufro rudfo urdfo rdufo drufo udrfo durfo frodu rfodu fordu ofrdu rofdu orfdu frdou rfdou fdrou dfrou rdfou drfou fodru ofdru fdoru dforu odfru dofru rodfu ordfu rdofu drofu odrfu dorfu fuodr ufodr foudr ofudr uofdr oufdr fudor ufdor fduor dfuor udfor dufor fodur ofdur fdour dfour odfur dofur uodfr oudfr udofr duofr odufr doufr ruodf urodf roudf orudf uordf ourdf rudof urdof rduof druof udrof durof roduf orduf rdouf drouf odruf doruf uodrf oudrf udorf duorf odurf dourf
Note: these 'words' (valid or invalid) are all the permutations of the word fruod. These words are obtained by scrambling the letters in fruod.