b-tree bbbbbb beebee beefer beegee beeker beeter befree befret begger bekker berbee berber bereet bereft berege bereke berere berger berker berrer berret bertre betere betete bettee better breefe breege breere breger bregge brekke brette ebbert eebree effere effete efreet efter- egbere egbert eggert ekberg erbree errett etgert fekete ferber ferfer fergee ferrer ferret fertee fertek ferter fetter frefre frette fterer fterre gbegbe gebbet gebert geegee gegger gekker gerber gerege gerger gerret gertte getter greefe greete greffe greger gregge gregre greter grette gteter k-tree kebber keefer keeffe keeker kegger kerber kereft kerker kertee ketter krefft kregbe kreker kretek r-tree reefer reeffe reeker refeet refeff refert refete refret refter regret reteer reteet retere retree retret retter t-tree teebee teetee teeter terete terrer terret terter tertre tetete tetter trebek treete trefet trefte treget treker tretee trette