bbb bbi bbo bbt bby bi- bib bii bio bit biy bob boi boo bot boy btb bti bto btt bty by- byi byo byt ibb ibi ibo ibt iby iib iii iio iit io- iob ioi ioo iot itb iti ito itt ity iyo iyt iyy o-i ob- obb obi obo obt oby oib oii oio oit oo- oob ooi ooo oot ot- otb oti oto ott oyi oyo tbb tbi tbo tbt tib tii tio tit tiy to- tob toi too tot toy ttb tti tto ttt tty tyo tyt ybi yby yii yio yit yob yoi yoo yot yoy yto ytt yyb yyt yyy