brith rbith birth ibrth ribth irbth brtih rbtih btrih tbrih rtbih trbih bitrh ibtrh btirh tbirh itbrh tibrh ritbh irtbh rtibh tribh itrbh tirbh briht rbiht birht ibrht ribht irbht brhit rbhit bhrit hbrit rhbit hrbit bihrt ibhrt bhirt hbirt ihbrt hibrt rihbt irhbt rhibt hribt ihrbt hirbt brthi rbthi btrhi tbrhi rtbhi trbhi brhti rbhti bhrti hbrti rhbti hrbti bthri tbhri bhtri hbtri thbri htbri rthbi trhbi rhtbi hrtbi thrbi htrbi bithr ibthr btihr tbihr itbhr tibhr bihtr ibhtr bhitr hbitr ihbtr hibtr bthir tbhir bhtir hbtir thbir htbir ithbr tihbr ihtbr hitbr thibr htibr rithb irthb rtihb trihb itrhb tirhb rihtb irhtb rhitb hritb ihrtb hirtb rthib trhib rhtib hrtib thrib htrib ithrb tihrb ihtrb hitrb thirb htirb
Note: these 'words' (valid or invalid) are all the permutations of the word brith. These words are obtained by scrambling the letters in brith.