bbbb bbdd bbdo bbpr bd-r bobb bobo bobu bodb bodo bodu boob bood boop boor bopp bor- bord boro borr boru boud boup bour bprd brdo brob brod broo bror brou brrr brud brup bubb bubo bubu budb budd budo budu bur- burb burd buro burp burr buru d-bo dbpd dddd ddpo ddub dobb dobu dod- dodd dodo doob dood doop door dopo dopp dopr dord doro dorp dorr doru doub doud doup dour drob drod drop drou drub drup druu dub- dubb dubu dudd dudo dudu duo- dupo duro duru duur obbo obor obro odbo oddd odoo odop odor odou odrp odur oooo oord opo- opor oppo orbb orbo orbu ordo ordu oro- oror orro orub orup our- ouro ouu- pdpr pobo pod- podd podo podu pood poop poor pop- popo popp porb poro porr poud poup pour ppod pppd pppo pppp ppru ppur pro- prob prod proo prop prou prpd prrd prud pruu pubu pudo pudu pupu pur- purb puro purp purr puru rbbb rbbr rdbp rob- robb robo robu rodd rodo roob rood roop roor ropo roro roru roub roud roup rpdp rpob rrrr rubb rubp rubu rudd rudo rudp rupp rurd ruro rurp ruru ruud u-rp ubbo ubod ubud udoo udop udpd uor- updo upor uppp uppu upup urdu uro- uroo urpo urup urur uuuu