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