a-ak a-be aaaa aaab aaae aaar aaba aabb aaea aaka aake aara aare abaa abab abae abak abar abax abb- abba abbb abbe abbr abee aber abra aeer aeka aer- aera akaa akae akar akee aker akka akr- akra akre arab arae arak arar arax arba arbe area aree arek arex arka arke arr- arra arre arrk arrr axar axer ba-x baaa baak baar baba babb babe babr baek baer bak- baka bake bakr bar- bara barb bare bark barr barx bbbb bbeb beak bear beba bebb bebe beeb beek beer beka beke bera bere berk berr brab brae brak brax brea breb bree brek brer brex brka brkb brrr eaba eara earb eare ebba ebbr eber eeea eeee eeka eeke eera eka- ekab ekeb ekek eker ekka er-x erba erbb erbe ereb erer erke erra erre exa- exer exrx kaaa kaab kaak kaar kaba kabb kabe kabr kaer kaka kake kakk kakx kara karb kare kark karr karx kaxa kaxe kbaa kbab kbae kbak kbar kbba kbbb kbbe kbbk kbbr kbeb kbee kbek kber kbex kbkb kbkk kbkr kbra kbrb kbre kbrk kbrx kbxb kbxr kbxx kea- keak kear keba kebb kebe kebr keek keer keka kekb keke ker- kera kerb kere kerk kerr kerx kexa kexb kexx kkaa kkar kkba kkbb kkbe kkbr kkea kkex kkkk kkrb kkre kkrk kkrr kkrx kkxa kkxk kkxx krab krae krak krar krba krbb krbe krbk krbr krbx krea kreb kree krek krex krka krke krkk krkr krkx krrb krre krrk krrr krrx krxa krxb krxk krxr krxx kxaa kxar kxba kxbr kxbx kxea kxex kxkk kxkx kxra kxrb kxre kxrk kxrr kxrx kxxe kxxk kxxr kxxx raab raak raba rabb rabe rabk raer raka rake rakk rara rarb rare rark raxa rbbb rbbr rea- reae reak rear reba rebb rebe rebk reeb reek reka reke rera rere rexx rrrr xaar xara xare xbar xbee xbra xeer xeka xer- xera xexe xxxx