a-be aaaa aaab aaae aaar aaba aabb aaea aaoe aaoo aara aare aaro aaru abaa abab abae abar abau abb- abba abbb abbe abbo abbr abee aber aboa abob aboo abor abou abra abro abua abue aeer aer- aera aero aoba aoeu aora aorb arab arae arar arau arba arbe area aree areo areu aroa arob aroe aroo aror arr- arra arre arro arrr arru arua arub arue auaa aube auer aur- aura aure auro baaa baar baba babb babe babo babr babu baer bar- bara barb bare baro barr baru bau- baur bbau bbbb bbeb bear beau beba bebb bebe bebo beeb beer beo- beor bera bere bero berr beru beur boab boar boba bobb bobe bobo bobu boea boee boeo boer boob booe boor bor- bora bore boro borr boru boua boue bour brab brae brao brau brea breb bree breo brer broa brob broe broo bror brou brrr brue buar buba bubb bube bubo bubu buea buer bueu bur- bura burb bure buro burr buru eaba eara earb eare earo ebba ebbo ebbr eber eboe eboo ebor ebro ebru ebur eeea eeee eera eero eora eore erau erba erbb erbe ereb erer erob eroe eroo erra erre erro erua erub erur euba euer eur- eura eure euro o-eo oaau oaer oara oare obba obbo obea ober oboe obor obra obre obro oera oere ooaa ooba oobe ooer oooo oora oore orab orae orao orar orba orbb orbe orbo orbu ore- orea oreb oreo orer oro- oroe oror orra orro orub ouea ouer our- oura oure ouro ouu- raab raba rabb rabe rabo rabu raer raob rara rarb rare raro raua raub raue rbbb rbbr rea- reae reao rear reau reba rebb rebe rebo rebu reeb reou rera rere rero reru reue reuu roab roar rob- roba robb robe robo robu roea roer roob roor rora rore roro roru roua roub roue rrrr ruba rubb rube rubu ruer rura rure ruro ruru uaru uaua ubar ubba ubbe ubbo uber ubra ueba uor- uore urao urau urba urbe ure- urea uro- uroa uroo urra urre urur uuuu