b-tree bbbbbb bebite beebee beefer beeter befree befret beiber berbee berber bereet bereft berere berrer berret berrie bertie bertre betere betete betire bettee better bettie bibber bibiri bieber biribi biteit bitier bitter bittie breefe breere breite brette bribe- bribee briber bribir bribri briefe ebbert ebr-ii ebrie eebree eerier effeir effere effete efreet efter- eibert eifert er-rif erbree erebti errett febri- feerie feifer feirie ferber ferfer ferier ferrer ferret ferri- ferrie fertee ferter fetter fibber fieber fiebre fiefie fierte fiftie firret fitbit fitter fittie fittit frebie frefre freire frette fterer fterie fterre i-beft i-bere i-bete i-free i-tree if-bet iffier ifreet irrite ittiri r-tree rebbit rebite reefer reeffe refeet refeff refert refete refire refrei refret refter reiber reiter reteer reteet retere retief retire retree retret retter ribber ribbet ribbie ribbit ribibe ribier rieber rieter riette rietti riffer rififi rifter rititi ritter t-tree tebbit teebee teetee teeter tefibi teirei terete teribe terrer terret terrie terrif territ terter tertre tetete tetter tibbit tiber- tibere tiberi tibert tibeti tibiri tibrie tiefer tierer tieret tiete tietie tiff-f tirret tirrit titbit titfer titiri tittee titter tittie treete trefet trefte treife tretee tretie trette tribit trifet triibe triter