b-tree bbbbbb becker becket beebee beeker beeter bekker berbee berber bercke bereet bereke berere berker berrer berret bertre betere betete bettee better breere brekke brette ceecee cerete creeke creete creket ebbert eckert eebree eerect erbree errett etcetc k-tree kebber keeker kerber kerker kertee ketter kreker kretek r-tree rebbec rebeck reeker retece reteer reteet retere retree retret retter t-tree teebee teetee teeter tercer tercet terete terrer terret terter tertre tetete tetter tr-rec trebce trebek treck- treece treete treker tretee trette