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