a-be aaaa aaab aaae aaar aaba aabb aaea aara aare aaru abaa abab abae abar abau abb- abba abbb abbe abbr abee aber abra abua abue aeer aer- aera arab arae arar arau arba arbe area aree areu arr- arra arre arrr arru arua arub arue auaa aube auer aur- aura aure baaa baar baba babb babe babr babu baer bar- bara barb bare barr baru bau- baur bbau bbbb bbeb bear beau beba bebb bebe beeb beer bera bere berr beru beur brab brae brau brea breb bree brer brrr brue buar buba bubb bube bubu buea buer bueu bur- bura burb bure burr buru eaba eara earb eare ebba ebbr eber ebru ebur eeea eeee eera erau erba erbb erbe ereb erer erra erre erua erub erur euba euer eur- eura eure raab raba rabb rabe rabu raer rara rarb rare raua raub raue rbbb rbbr rea- reae rear reau reba rebb rebe rebu reeb rera rere reru reue reuu rrrr ruba rubb rube rubu ruer rura rure ruru uaru uaua ubar ubba ubbe uber ubra ueba urau urba urbe ure- urea urra urre urur uuuu