grues rgues gures ugres ruges urges greus rgeus gerus egrus regus ergus guers ugers geurs egurs uegrs eugrs ruegs uregs reugs erugs uergs eurgs gruse rguse gurse ugrse rugse urgse grsue rgsue gsrue sgrue rsgue srgue gusre ugsre gsure sgure usgre sugre rusge ursge rsuge sruge usrge surge gresu rgesu gersu egrsu regsu ergsu grseu rgseu gsreu sgreu rsgeu srgeu gesru egsru gseru sgeru esgru segru resgu ersgu rsegu sregu esrgu sergu guesr ugesr geusr egusr uegsr eugsr guser ugser gsuer sguer usger suger gesur egsur gseur sgeur esgur segur uesgr eusgr usegr suegr esugr seugr ruesg uresg reusg erusg uersg eursg ruseg urseg rsueg srueg usreg sureg resug ersug rseug sreug esrug serug uesrg eusrg userg suerg esurg seurg
Note: these 'words' (valid or invalid) are all the permutations of the word grues. These words are obtained by scrambling the letters in grues.