-tree bbbee be-er beber beebe beete beeut begee beget begge begue begur begut berbe bereg beret berge berre berru berte betee beter betre bett- bette beuer beure beute brebu breer breet breg- brege bregg brere brett breu- brrrr bruer bruet bruge brugg brute btr-t bubbe buber buger bugge bugre buret burge burgu burru burte burtt burut buter butte butut ebber ebbet eberg ebert ebure eeeee egger egret erbbe erber erege erere errtu erte erter ertug etete etree etter eturu eurre gberg gberu geber gebet gebre gebur geere geert geete gegge gerbe gerre gertt getee geter gette grebe greer greet grege gregg grete grett greut grgur grrrr grubb grube grure gruut gtube gubbe guber gubru guere gurge gurre gurur gutte rebbe rebeg reber rebet rebut reege reere reger reget regge regtt regur regut rere- reree reret retee reter retrg rette reuer reuet reute rubee ruber ruegg ruere ruete ruger ruget rugge ruter rutte ruutu tbtbt tbutt teber tebet teege tegre tegur teret tereu terge tergu terre tert- teter tetr- tette teuge treer treet treg- trere trete trett treut trubu truer trugg trute ttttt tuber turbe turbt turet turre turtu turut tutee tutte tuuru uber- ugrug urger urgut urter urubu urutu uter- utter uttur utube uturu uuuuu