bbbb bbdd bbdo bbeb bd-r bebb bebe bebo bede bedo bedu beeb beed beer beo- beod beor berd bere bero berr beru beur bobb bobe bobo bobu bodb bode bodo bodu boee boeo boer boob bood booe boor bor- bord bore boro borr boru boud boue bour brdo breb bred bree breo brer brob brod broe broo bror brou brrr brud brue bubb bube bubo bubu budb budd bude budo budu buer bueu bur- burb burd bure buro burr buru d-bo dddd ddre ddub debe debu dedd dede dedo dedu deeb deed deer deor der- derb dere dero derr deue deur dobb dobe dobu dod- dodd dode dodo doer doob dood door dord dore doro dorr doru doub doud doue dour dred dree drob drod drou drub drue druu dub- dubb dube dubu dudd dude dudo dudu duer duo- dure duro duru duur ebbo ebbr ebed eber eboe eboo ebor ebro ebru ebur edde eddo ede- eder edod edou edru edur eede eedu eeee eero eode eore erbb erbe erde ereb ered erer erob erod eroe eroo erre erro erub erur eude euer eur- eure euro o-eo obbo obed ober oboe obor obre obro odbo oddd oded odeo oder odoo odor odou odur oedo oere oobe ooer oooo oord oore orbb orbe orbo orbu orde ordo ordu ore- oreb ored oreo orer oro- oroe oror orro orub oude oued ouer our- oure ouro ouu- rbbb rbbr rder rebb rebe rebo rebu redd rede redo redr redu reeb reed reod reou rerd rere rero reru reue reuu rob- robb robe robo robu rodd rode rodo roed roer roob rood roor rore roro roru roub roud roue rred rrrr rubb rube rubu rudd rude rudo rued ruer rurd rure ruro ruru ruud ubbe ubbo uber ubod ubud uder udoo uor- uore urbe urde urdu ure- ured uro- uroo urre urur uuuu