biers ibers beirs ebirs iebrs eibrs bires ibres bries rbies irbes ribes beris ebris breis rbeis erbis rebis ierbs eirbs irebs riebs eribs reibs biesr ibesr beisr ebisr iebsr eibsr biser ibser bsier sbier isber siber besir ebsir bseir sbeir esbir sebir iesbr eisbr isebr siebr esibr seibr birse ibrse brise rbise irbse ribse bisre ibsre bsire sbire isbre sibre brsie rbsie bsrie sbrie rsbie srbie irsbe risbe isrbe sirbe rsibe sribe bersi ebrsi bresi rbesi erbsi rebsi besri ebsri bseri sberi esbri sebri brsei rbsei bsrei sbrei rsbei srbei ersbi resbi esrbi serbi rsebi srebi iersb eirsb iresb riesb erisb reisb iesrb eisrb iserb sierb esirb seirb irseb riseb isreb sireb rsieb srieb ersib resib esrib serib rseib sreib
Note: these 'words' (valid or invalid) are all the permutations of the word biers. These words are obtained by scrambling the letters in biers.