brieb rbieb bireb ibreb ribeb irbeb breib rbeib berib ebrib rebib erbib bierb iberb beirb ebirb iebrb eibrb riebb irebb reibb eribb ierbb eirbb bribe rbibe birbe ibrbe ribbe irbbe brbie rbbie bbrie bbrie rbbie brbie bibre ibbre bbire bbire ibbre bibre ribbe irbbe rbibe bribe ibrbe birbe brebi rbebi berbi ebrbi rebbi erbbi brbei rbbei bbrei bbrei rbbei brbei bebri ebbri bberi bberi ebbri bebri rebbi erbbi rbebi brebi ebrbi berbi biebr ibebr beibr ebibr iebbr eibbr biber ibber bbier bbier ibber biber bebir ebbir bbeir bbeir ebbir bebir iebbr eibbr ibebr biebr ebibr beibr riebb irebb reibb eribb ierbb eirbb ribeb irbeb rbieb brieb ibreb bireb rebib erbib rbeib breib ebrib berib iebrb eibrb iberb bierb ebirb beirb
Note: these 'words' (valid or invalid) are all the permutations of the word brieb. These words are obtained by scrambling the letters in brieb.