-er bbb bbc bbe bbo bbr bbt bcb bcc bce bco bcr bct be- beb bec bee beo ber bet bob boc boe boo bor bot brb bre bro brr brt btb btc bte bto btr btt c-- cbb cbc cbe cbo cbr cbt ccb ccc cce cco ccr cct ce- ceb cec cee ceo cer cet co- cob coc coe coo cor cot crb crc cre cro crr crt ctb ctc cte cto ctr ctt ebb ebc ebe ebo ebr ebt ec- ecb ecc ece eco ecr ect eeb eec eee eeo eer eet eo- eob eoc eoe eoo eor eot erb erc ere ero err ert etb etc ete eto etr ett ob- obb obc obe obo obr obt oc- ocb occ oco ocr oct oeb oec oee oeo oer oet oo- oob ooc ooo oor oot or- orb orc ore oro orr ort ot- otb otc ote oto otr ott rbb rbc rbe rbo rbr rbt rcb rcc rce rco rcr rct re- reb rec ree reo rer ret rob roc roe roo ror rot rrb rrc rrr rrt rtb rtc rte rto rtr rtt tbb tbc tbe tbo tbr tbt tcb tcc tce tco tcr tct te- teb tec tee teo ter tet to- tob toc toe too tor tot trb trc tre tro trr trt ttb ttc tte tto ttr ttt

bbbb bbeb bbet bbrc bcbc bccc bcec bcer bcet bcor bctc bebb bebe bebo beeb beer beet beo- beor beot berc bere bero berr bert betc bete beto bett bobb bobe bobo boce boco boec boee boeo boer boet boob booc booe boor boot bor- bore boro borr bort botb bote boto bott brcb brce breb brec bree breo brer bret brob broc broe broo bror brot brrr brtc btcc btec btob btor btrc btrt bttb c-bo cbbc cbcc cbce cbcr cbct cbec cbee cber cbet cbot cbre cbrt cbtc ccbc cccb cccc ccee ccob ccoc ccrc ccre ccrt cctb cctc cctt cec- cece ceco cect ceeb ceec ceor cer- cerc cere cero cert cet- cete ceto cobb cobe cobo coce coco coct coob coot cor- corb corc core coro corr cort cotb cotc cote coto cott crbc crcc crce crcr cre- creb crec cree creo cret crob croc croe croo cror crot crrt crtc ctec ctor ctot ctrc ebbc ebbo ebbr ebcc eber eboe eboo ebor ebro ecbc ecbe eccb eccc ecce ecco ecct eco- ecot ecrc ecrr ect- ectc ecto eeee eeoc eerc eero eetc eete eore eotc eoto erbb erbe ercc erce ereb erec erer eret erob eroc eroe eroo errc erre erro etbc etbr etcc etco etec etee eter etoe etre etro ette etto o-eo obbo obec ober obet oboe obor obot obre obro ocbc occc occt oce ocee ocet ocre ocro ocrr oct- octe octo oec- oecc oeec oere oobe oocr ooer oooo oore oort ootb orbb orbe orbo orce orco ore- oreb orec oreo orer oro- oroe oror orot orro ortc orte orto otee oter oto- otoe otoo otor otre otro otte otto rbbb rbbr rcbc rcbo rccb rccc rcet rctc rebb rebe rebo recc rece recr rect reeb reet reot rere rero rert rete reto retr rett rob- robb robe robo robt rocc roce roco roer roet roob roor root rorc rore roro rort rotc rote roto rotr rott rrrr rtcc rtce rtee tbcb tbcc tbce tbrb tccc tctc tebo teco tecr tect teec teer teet teor ter- terc tere tero terr tete teto tetr tett tobe tobo tobt toce toco toee toer toet toor toot torc tore toro torr tort totc tote toto totr tott trcc tre- trec tree treo tret troc troe troo trot trtc trte trtr ttbb tteo tter ttoe tttt

-tree bbbee be-er be-ro beber bebot becco beebe beete beote berbe berec beret berob beroe beror berre berte berto betee beter betoo betor betre bett- bette betto bo-bo bobet boboc bobr bobre bocce bocet bocor boece boero booce booco booer boore boort borbo borce borec boree borer boret boro- boroo borot borre borro botet botro botte brece breer breet breo- breoc brere breto brett brobo broce broer broto brrrr btc-e btr-t c-cor c-tec ccccc ccett cebec ceber ceco- ceere ceoce ceoor cerc- cerce cerco cerec cerer ceret cero- ceroc cerre cerro certe ceto- cette co-bo co-co cobbe cobot cobre cocc- cocce cocco coceo cocto coete cooee cooer coore coote corbe corbo corce core- coree corer coro- corot corre corte corto coter cott- cotte cotto crebe crece creer creo- creot crete croce croco crooe croot crore crote crott ctree cttee ebber ebbet ebert ecto- ector ectot eeeee eorre erbbe erber erect erere eroor erore eroto error erte erter etete etoro etree etter o-r-b obbet obert obete oboro obote obreb ocoee ocote ocr-b ocree octet octo- octor oeco- oo-er oocre ooooo orbec orbot orcet oreco oreo- orere orero orobe orobo oroco oroer orret orter ortet ortoo otcbb otere otero otoce ototo otter r-co- rebbe rebec reber rebet recce recco recet rect- recte recto reece reere rere- reree reret rerob retee reter retro rette retto ro-ro robbe robbo robec rober robo- robor robot robrt robte rocco rocor roero rooer roore roote rorer roteb roter roto- rotor rotot rotte rotto tbtbt tcobb teber tebet tectb teoco terce terco teret teror terre terro tert- teter tetr- tetro tette to-be tobbe tober tobet tobor tobot tobre tocco toco- toece toerr toeto toobe toore torbe torce toreo toret torob torre torro torte torto toter toto- totoe totoo totte trboc treco treer treet trere trete trett troco troee trott ttttt

b-tree bbbbbb bebeto beebee beeter berbee berbeo berber berceo bereet berere berrer berret bertre betere betete bettee better bettor bobber bobete bobote boccob boeber boerre boober booboo bootee booter borbor boreto borore bororo borte botere botero botete botoro botree botter breere brette brocco brocor brocot broter brotto ceecee cerco- cerete cerote certco cetore cobber cobbob cocco- cococo cocto- coerce coo-er coocoo cooter corbet corect corteo cortot cotote cotter crecco creete creote crobot crocco crocer croote ebbert ecobee ecobot ecotec ectro- eebree