burbs ubrbs brubs rbubs urbbs rubbs bubrs ubbrs bburs bburs ubbrs bubrs brbus rbbus bbrus bbrus rbbus brbus urbbs rubbs ubrbs burbs rbubs brubs bursb ubrsb brusb rbusb urbsb rubsb busrb ubsrb bsurb sburb usbrb subrb brsub rbsub bsrub sbrub rsbub srbub ursbb rusbb usrbb surbb rsubb srubb bubsr ubbsr bbusr bbusr ubbsr bubsr busbr ubsbr bsubr sbubr usbbr subbr bbsur bbsur bsbur sbbur bsbur sbbur ubsbr busbr usbbr subbr bsubr sbubr brbsu rbbsu bbrsu bbrsu rbbsu brbsu brsbu rbsbu bsrbu sbrbu rsbbu srbbu bbsru bbsru bsbru sbbru bsbru sbbru rbsbu brsbu rsbbu srbbu bsrbu sbrbu urbsb rubsb ubrsb bursb rbusb brusb ursbb rusbb usrbb surbb rsubb srubb ubsrb busrb usbrb subrb bsurb sburb rbsub brsub rsbub srbub bsrub sbrub
Note: these 'words' (valid or invalid) are all the permutations of the word burbs. These words are obtained by scrambling the letters in burbs.