b-tree bbbbbb bedded bedder bedebt beduru beebee beedee beerde beeter berbee berber berede bereet berere berrer berret bertre berube betere betete betrue betted bettee better betutu beurre bredde breded breder breede breere brette breuer brubru bruder brudet brurde bruree bruted bubber bububu budded budder burbet burbur burder burdet burdur burred burree burrer burret burutu butere butted butter dbette de-err debdeb debere debert debete debret debted debtee deburr dedute deeded deedee deeder derere derrer derure deterr detete detter deturb deubre deuter dreder druber dubbed dubber dubdub dudder duerer dueted duetee duette duttee ebbert eburru eebree erbree errett ettutu eutere r-tree rebred rebute redbed redbud redded redder reddur redere redred redted redure reeded reeder reteed reteer reteet retere retree retret retted retter rettur retube returu reuere reuter reutte rubbed rubbee rubber rubutu rudder rudrur rurutu rutted ruttee rutter rutube t-tree t-tube tebedu tedded tedder tedure teebee teeder teetee teeter terete terrer terret terter tertre tetede tetete tetter trebur treder treete tretee trette truett tubbed tubber tudder turbet turret turtur tururu tuteur tutted tutter tuttut u-tube ubered udburu urdeur ureter urette uteute