aaaa aaab aaar aaav aaba aabb aabt aaoo aara aaro aart aata aatt aava abaa abab abar abat abb- abba abbb abbo abbr abbt aboa abob aboo abor abot abov abra abro abta abva aoba aora aorb aort arab arar arat arba aroa arob aroo aror arr- arra arro arrr arrt arta arto artr artv arva arvo at-t ataa atab atar atat atob ator atot atra atro atta atto attr avab avao avar avat avor avot avra avro avva avvo baaa baar baat baba babb babo babr bar- bara barb baro barr bart bata bato batt bava bbbb boab boar boat boba bobb bobo boob boor boot bor- bora boro borr bort bota botb boto bott bova bovo brab brao brat brav broa brob broo bror brot brrr btaa btob btor btrt bttb oara obba obbo obor obot obra obro ooaa ooba oooo oora oort ootb orab orao orar orat orav orba orbb orbo oro- oror orot orra orro orta orto orvr otar oto- otoo otor otov otra otro otta otto ovar ovo- ovoo ovot ovra raab raat raba rabb rabo raob rara rarb raro rata rato ratt rava rbbb rbbr roab roar roat rob- roba robb robo robt roob roor root rora roro rort rota roto rotr rott rova rovo rrat rrrr rtva taa- taar taat taba tabb tabo taoa taor tara tarb taro tarr tart tata tatb tato tatr tatt tatv tava tavo tbar tbrb tbta toab toat toba tobo tobt tooa toor toot tora toro torr tort torv tota toto totr tott tova tovo traa trab trao trat trav troa troo trot trra trtr ttab ttbb tttt tvro tvrr tvtv vaar vaat vara varr vart vata vato vatt vava voar voat voor voot vor- vora voro vort vota voto vrav vrba vrot vrto vvob vvvv