bbbb bnor bnrr bobb bobo bonn bono bont boob boon boor boot bor- born boro borr bort botb botn boto bott brno brob bron broo bror brot brrr btob btor btrt bttb nbbo nnnn nnot nntn nobo non- nonn nono nont noo- noob noon nooo noor noot nor- norb norn noro norr nort not- noto nott nron ntto nttr obbo obon obor obot obro onno onon onor ont- onto oont oooo oort ootb orbb orbo orno oro- oron oror orot orro orto oto- oton otoo otor otro otto rbbb rbbr rnbr rnnt rnot rob- robb robo robt rono ront roob roon roor root roro rort rotn roto rotr rott rrrr tbrb tobo tobt tonb tonn tono toon toor toot torn toro torr tort toto totr tott trno tron troo trot trtr ttbb tton tttt