a-be aaaa aaab aaae aaar aaba aabb aaea aara aare abaa abab abae abar abax abb- abba abbb abbe abbr abee aber abra aeer aer- aera arab arae arar arax arba arbe area aree arex arr- arra arre arrr axar axer ba-x baaa baar baba babb babe babr baer bar- bara barb bare barr barx bbbb bbeb bear beba bebb bebe beeb beer bera bere berr brab brae brax brea breb bree brer brex brrr eaba eara earb eare ebba ebbr eber eeea eeee eera er-x erba erbb erbe ereb erer erra erre exa- exer exrx raab raba rabb rabe raer rara rarb rare raxa rbbb rbbr rea- reae rear reba rebb rebe reeb rera rere rexx rrrr xaar xara xare xbar xbee xbra xeer xer- xera xexe xxxx