bbb bbo bbr bbt bby bob boo bor bot boy brb bro brr brt bry btb bto btr btt bty by- byo byr byt ob- obb obo obr obt oby oo- oob ooo oor oot or- orb oro orr ort ory ot- otb oto otr ott oyo rbb rbo rbr rbt rob roo ror rot roy rrb rrr rrt rtb rto rtr rtt rty ry- ryo ryr ryy tbb tbo tbr tbt to- tob too tor tot toy trb tro trr trt try ttb tto ttr ttt tty tyo tyr tyt ybr yby yob yoo yor yot yoy yro yrt yto ytr ytt yyb yyt yyy