bbb bbi bbo bbt bi- bib bii bio bit biv bob boi boo bot bov btb bti bto btt btv bvb bvi bvo bvt bvv i-v ibb ibi ibo ibt ibv iib iii iio iit io- iob ioi ioo iot iov itb iti ito itt itv ivb ivi ivo ivt ivv o-i ob- obb obi obo obt obv oib oii oio oit oiv oo- oob ooi ooo oot oov ot- otb oti oto ott otv ov- ovb ovi ovo ovv tbb tbi tbo tbt tbv tib tii tio tit tiv to- tob toi too tot tov ttb tti tto ttt ttv tvb tvi tvo tvt vbi vbo vbv vi- vib vii vio vit viv vob voi voo vot vov vtb vti vto vtt vtv vvb vvi vvo vvt vvv