bbb bbi bbo bbr bbt bi- bib bii bio bir bit biz bob boi boo bor bot boz brb bri bro brr brt brz btb bti bto btr btt btz bzo bzr bzz ibb ibi ibo ibr ibt ibz iib iii iio iir iit io- iob ioi ioo ior iot ir- irb iri iro irr irt itb iti ito itt itz izi izo izz o-i ob- obb obi obo obr obt oib oii oio oir oit oiz oo- oob ooi ooo oor oot or- orb ori oro orr ort orz ot- otb oti oto otr ott otz ozo ozt ozz rbb rbi rbo rbr rbt rib rii rio rir rit riz rob roi roo ror rot roz rrb rri rrr rrt rtb rti rto rtr rtt rtz rzb rzo tbb tbi tbo tbr tbt tbz tib tii tio tir tit tiz to- tob toi too tor tot toz trb tri tro trr trt trz ttb tti tto ttr ttt zbb zbr zbt zib zio zir zit ziz zo- zob zoi zoo zor zot zro ztr zzr zzt zzz