bbbb bbdd bbeb bbet bd-r bebb bebe bede bedu beeb beed beer beet berd bere berr bert beru bete bett betu beur brdt breb bred bree brer bret brrr brud brue brut btdt btrt bttb bubb bube bubu budb budd bude budu buer bueu bur- burb burd bure burr burt buru but- bute butt dbtt dddd ddre ddub debe debt debu dedd dede dedu deeb deed deer deet der- derb dere derr dete detr deue deur deut dred dree dret drub drue drut druu dted dub- dubb dube dubu dudd dude dudu duer duet dure durt duru dute duur duut ebbr ebed eber ebru ebur edde ede- eder edru edur eede eedu eeee eete eetu erbb erbe erde ereb ered erer eret erre ertu erub erur etbr etee eter etre ette ettu eude euer eur- eure eurt rbbb rbbr rder rebb rebe rebu redd rede redr redu reeb reed reet rerd rere rert reru retd rete retr rett reue reut reuu rred rrrr rtdt rtee rubb rube rubu rudd rude rued ruer ruet rurd rure ruru rute rutt rutu ruud tbrb tddb tebu tedd tede teed teer teet ter- tere terr teru tete tetr tett tetu teut tre- tred tree tret treu trte trtr trub trud true trut truu ttbb tter tttt tubb tube tubr tubu tude tudu tuer tuet turb turd ture turr turt turu tute tutt tutu ubbe uber ubet ubud uder udet urbe urde urdu ure- ured uret urre urte urur urut uter uttu uuuu