birls ibrls brils rbils irbls ribls bilrs iblrs blirs lbirs ilbrs librs brlis rblis blris lbris rlbis lrbis irlbs rilbs ilrbs lirbs rlibs lribs birsl ibrsl brisl rbisl irbsl ribsl bisrl ibsrl bsirl sbirl isbrl sibrl brsil rbsil bsril sbril rsbil srbil irsbl risbl isrbl sirbl rsibl sribl bilsr iblsr blisr lbisr ilbsr libsr bislr ibslr bsilr sbilr isblr siblr blsir lbsir bslir sblir lsbir slbir ilsbr lisbr islbr silbr lsibr slibr brlsi rblsi blrsi lbrsi rlbsi lrbsi brsli rbsli bsrli sbrli rsbli srbli blsri lbsri bslri sblri lsbri slbri rlsbi lrsbi rslbi srlbi lsrbi slrbi irlsb rilsb ilrsb lirsb rlisb lrisb irslb rislb isrlb sirlb rsilb srilb ilsrb lisrb islrb silrb lsirb slirb rlsib lrsib rslib srlib lsrib slrib
Note: these 'words' (valid or invalid) are all the permutations of the word birls. These words are obtained by scrambling the letters in birls.