b-u bbb bbo bbr bbt bbu bby bob boo bor bot bou boy brb bro brr brt bru bry btb bto btr btt btu bty bub buo bur but buu buy by- byo byr byt byu ob- obb obo obr obt obu oby oo- oob ooo oor oot or- orb oro orr ort oru ory ot- otb oto otr ott otu ou- ouo our out oyo rbb rbo rbr rbt rbu rob roo ror rot rou roy rrb rrr rrt rru rtb rto rtr rtt rtu rty rub ruo rur rut ruu ruy ry- ryo ryr ryu ryy tbb tbo tbr tbt tbu to- tob too tor tot tou toy trb tro trr trt tru try ttb tto ttr ttt ttu tty tub tuo tur tut tuu tuy tyo tyr tyt ubb ubo ubr ubt ubu uby uob uoo uor uot ur- urb uro urr urt uru ury utb uto utr utt utu uty uur uut uuu uyo uyu ybr yby yob yoo yor yot you yoy yro yrt yru yto ytr ytt ytu yuo yur yut yuu yuy yyb yyt yyu yyy