durns udrns druns rduns urdns rudns dunrs udnrs dnurs ndurs undrs nudrs drnus rdnus dnrus ndrus rndus nrdus urnds runds unrds nurds rnuds nruds dursn udrsn drusn rdusn urdsn rudsn dusrn udsrn dsurn sdurn usdrn sudrn drsun rdsun dsrun sdrun rsdun srdun ursdn rusdn usrdn surdn rsudn srudn dunsr udnsr dnusr ndusr undsr nudsr dusnr udsnr dsunr sdunr usdnr sudnr dnsur ndsur dsnur sdnur nsdur sndur unsdr nusdr usndr sundr nsudr snudr drnsu rdnsu dnrsu ndrsu rndsu nrdsu drsnu rdsnu dsrnu sdrnu rsdnu srdnu dnsru ndsru dsnru sdnru nsdru sndru rnsdu nrsdu rsndu srndu nsrdu snrdu urnsd runsd unrsd nursd rnusd nrusd ursnd rusnd usrnd surnd rsund srund unsrd nusrd usnrd sunrd nsurd snurd rnsud nrsud rsnud srnud nsrud snrud
Note: these 'words' (valid or invalid) are all the permutations of the word durns. These words are obtained by scrambling the letters in durns.