-tree bbbee be-er beber beebe beete beeut bembe bemer bemet berbe beret berme berre berru berte berum betee beter betre bett- bette beuer beure beute brebu breem breer breet breme bremm brere brett breu- brmmm brrrr bruer bruet brume brumm brute btr-t bubbe buber bumbu bumme buret burru burte burtt burut buter butme butte butut ebber ebbet ebert ebure eeeee embee ember embue emeer emere emert emmer emmet emtee emure erbbe erber erem- erere errtu erte erter etete etree etter eturu eum-u eurre mbebe mbere mbret mbube mburu mebbe meemu meere meete membe memer merer meret merre merte merur meter metr- metre mette metur meuer meure meute mmmmm mreru mrmet mt-te mt-tm mt-tr mt-tt mtree mtume mumbe mumme mummu muret mureu murre murru murum murut muter mutet mutum rebbe reber rebet rebut reeme reere remee remer remet remue rere- reree reret rerum retee retem reter rette reuer reuet reume reute rmutt rubee ruber ruere ruete rumbe rumer rummu ruter rutte ruutu tbtbt tbutt teber tebet teeme teemu tembe tembu terem teret tereu terme terre tert- teter tetr- tette treer treet treme trere trete trett treut trubu truer trume trute ttttt tuber tumbe tumbu tumut turbe turbt turem turet turre turtu turut tutee tutte tuuru uber- ubume umbe- umber umbre umeer umeme ureme urter urubu urutu uter- utmer utrum utter uttur utube uturu uuuuu