b-tree bbbbbb bebite beebee beeter beiber berbee berber bereet berere berrer berret berrie bertie bertre betere betete betire bettee better bettie bibber bibiri bieber biribi biteit bitier bitter bittie breere breite brette bribe- bribee briber bribir bribri ebbert ebr-ii ebrie eebree eerier eibert erbree erebti errett i-bere i-bete i-tree irrite ittiri r-tree rebbit rebite reiber reiter reteer reteet retere retire retree retret retter ribber ribbet ribbie ribbit ribibe ribier rieber rieter riette rietti rititi ritter t-tree tebbit teebee teetee teeter teirei terete teribe terrer terret terrie territ terter tertre tetete tetter tibbit tiber- tibere tiberi tibert tibeti tibiri tibrie tierer tieret tiete tietie tirret tirrit titbit titiri tittee titter tittie treete tretee tretie trette tribit triibe triter