furan ufran fruan rfuan urfan rufan fuarn ufarn faurn afurn uafrn aufrn fraun rfaun farun afrun rafun arfun urafn ruafn uarfn aurfn raufn arufn furna ufrna fruna rfuna urfna rufna funra ufnra fnura nfura unfra nufra frnua rfnua fnrua nfrua rnfua nrfua urnfa runfa unrfa nurfa rnufa nrufa fuanr ufanr faunr afunr uafnr aufnr funar ufnar fnuar nfuar unfar nufar fanur afnur fnaur nfaur anfur nafur uanfr aunfr unafr nuafr anufr naufr franu rfanu farnu afrnu rafnu arfnu frnau rfnau fnrau nfrau rnfau nrfau fanru afnru fnaru nfaru anfru nafru ranfu arnfu rnafu nrafu anrfu narfu uranf ruanf uarnf aurnf raunf arunf urnaf runaf unraf nuraf rnuaf nruaf uanrf aunrf unarf nuarf anurf naurf ranuf arnuf rnauf nrauf anruf naruf
Note: these 'words' (valid or invalid) are all the permutations of the word furan. These words are obtained by scrambling the letters in furan.