bbb bbi bbo bbr bi- bib bii bio bir biz bob boi boo bor boz brb bri bro brr brz bzo bzr bzz ibb ibi ibo ibr ibz iib iii iio iir io- iob ioi ioo ior ir- irb iri iro irr izi izo izz o-i ob- obb obi obo obr oib oii oio oir oiz oo- oob ooi ooo oor or- orb ori oro orr orz ozo ozz rbb rbi rbo rbr rib rii rio rir riz rob roi roo ror roz rrb rri rrr rzb rzo zbb zbr zib zio zir ziz zo- zob zoi zoo zor zro zzr zzz