burrs ubrrs brurs rburs urbrs rubrs burrs ubrrs brurs rburs urbrs rubrs brrus rbrus brrus rbrus rrbus rrbus urrbs rurbs urrbs rurbs rrubs rrubs bursr ubrsr brusr rbusr urbsr rubsr busrr ubsrr bsurr sburr usbrr subrr brsur rbsur bsrur sbrur rsbur srbur ursbr rusbr usrbr surbr rsubr srubr bursr ubrsr brusr rbusr urbsr rubsr busrr ubsrr bsurr sburr usbrr subrr brsur rbsur bsrur sbrur rsbur srbur ursbr rusbr usrbr surbr rsubr srubr brrsu rbrsu brrsu rbrsu rrbsu rrbsu brsru rbsru bsrru sbrru rsbru srbru brsru rbsru bsrru sbrru rsbru srbru rrsbu rrsbu rsrbu srrbu rsrbu srrbu urrsb rursb urrsb rursb rrusb rrusb ursrb rusrb usrrb surrb rsurb srurb ursrb rusrb usrrb surrb rsurb srurb rrsub rrsub rsrub srrub rsrub srrub
Note: these 'words' (valid or invalid) are all the permutations of the word burrs. These words are obtained by scrambling the letters in burrs.