bbb bbi bbk bbo bi- bib bii bik bio biv bkb bkk bko bkv bob boi bok boo bov bvb bvi bvk bvo bvv i-v ibb ibi ibk ibo ibv iib iii iio ikb iki ikk iko ikv io- iob ioi ioo iov ivb ivi ivo ivv kbb kbi kbk kbo kib kii kik kio kiv kkb kki kkk kkv kob koi kok koo kvb kvi kvk kvo kvv o-i ob- obb obi obk obo obv oib oii oik oio oiv okb oki okk oko oo- oob ooi ook ooo oov ov- ovb ovi ovo ovv vbi vbk vbo vbv vi- vib vii vik vio viv vkb vob voi vok voo vov vvb vvi vvo vvv