-er b-u bbb bbe bbr bbt bbu be- beb bee ber bet beu brb bre brr brt bru btb bte btr btt btu bub bue bur but buu ebb ebe ebr ebt ebu eeb eee eer eet erb ere err ert eru etb ete etr ett etu eu- eub eue eur eut rbb rbe rbr rbt rbu re- reb ree rer ret reu rrb rrr rrt rru rtb rte rtr rtt rtu rub rue rur rut ruu tbb tbe tbr tbt tbu te- teb tee ter tet teu trb tre trr trt tru ttb tte ttr ttt ttu tub tue tur tut tuu ubb ube ubr ubt ubu ueb uee uer uet ur- urb ure urr urt uru utb ute utr utt utu uue uur uut uuu

bbbb bbeb bbet bebb bebe beeb beer beet bere berr bert beru bete bett betu beur breb bree brer bret brrr brue brut btrt bttb bubb bube bubu buer bueu bur- burb bure burr burt buru but- bute butt ebbr eber ebru ebur eeee eete eetu erbb erbe ereb erer eret erre ertu erub erur etbr etee eter etre ette ettu euer eur- eure eurt rbbb rbbr rebb rebe rebu reeb reet rere rert reru rete retr rett reue reut reuu rrrr rtee rubb rube rubu ruer ruet rure ruru rute rutt rutu tbrb tebu teer teet ter- tere terr teru tete tetr tett tetu teut tre- tree tret treu trte trtr trub true trut truu ttbb tter tttt tubb tube tubr tubu tuer tuet turb ture turr turt turu tute tutt tutu ubbe uber ubet urbe ure- uret urre urte urur urut uter uttu uuuu

-tree bbbee be-er beber beebe beete beeut berbe beret berre berru berte betee beter betre bett- bette beuer beure beute brebu breer breet brere brett breu- brrrr bruer bruet brute btr-t bubbe buber buret burru burte burtt burut buter butte butut ebber ebbet ebert ebure eeeee erbbe erber erere errtu erte erter etete etree etter eturu eurre rebbe reber rebet rebut reere rere- reree reret retee reter rette reuer reuet reute rubee ruber ruere ruete ruter rutte ruutu tbtbt tbutt teber tebet teret tereu terre tert- teter tetr- tette treer treet trere trete trett treut trubu truer trute ttttt tuber turbe turbt turet turre turtu turut tutee tutte tuuru uber- urter urubu urutu uter- utter uttur utube uturu uuuuu

b-tree bbbbbb beebee beeter berbee berber bereet berere berrer berret bertre berube betere betete betrue bettee better betutu beurre breere brette breuer brubru bruree bubber bububu burbet burbur burree burrer burret burutu butere butter ebbert eburru eebree erbree errett ettutu eutere r-tree rebute reteer reteet retere retree retret retter rettur retube returu reuere reuter reutte rubbee rubber rubutu rurutu ruttee rutter rutube t-tree t-tube teebee teetee teeter terete terrer terret terter tertre tetete tetter trebur treete tretee trette truett tubber turbet turret turtur tururu tuteur tutter tuttut u-tube ureter urette uteute

bbbbbbb bebeeru beetree berbere berrett bertree brutter burbure burette reteere reterre retrete rettert reutter tebbutt terere terreer terrere tettete treetee trettre truebut turbett tut-tut ub-tree utterer

bbbbbbbb bebetter bebutter bee-butt berebere betterer bruterer bubertre bur-tree buruburu etbetter rebutter teruteru

beebeebee butterbur ettubrute tebe-tebe

berberburr betterbeer rubbertree

ettutubrute ueberreuter

bbbbbbbbbbbbbbb