unbid nubid ubnid bunid nbuid bnuid unibd nuibd uinbd iunbd niubd inubd ubind buind uibnd iubnd biund ibund nbiud bniud nibud inbud binud ibnud unbdi nubdi ubndi bundi nbudi bnudi undbi nudbi udnbi dunbi ndubi dnubi ubdni budni udbni dubni bduni dbuni nbdui bndui ndbui dnbui bdnui dbnui unidb nuidb uindb iundb niudb inudb undib nudib udnib dunib nduib dnuib uidnb iudnb udinb duinb idunb diunb nidub indub ndiub dniub idnub dinub ubidn buidn uibdn iubdn biudn ibudn ubdin budin udbin dubin bduin dbuin uidbn iudbn udibn duibn idubn diubn bidun ibdun bdiun dbiun idbun dibun nbidu bnidu nibdu inbdu bindu ibndu nbdiu bndiu ndbiu dnbiu bdniu dbniu nidbu indbu ndibu dnibu idnbu dinbu bidnu ibdnu bdinu dbinu idbnu dibnu
Note: these 'words' (valid or invalid) are all the permutations of the word unbid. These words are obtained by scrambling the letters in unbid.