bbbb bibb bibi bibo bio- bioi biot birb biri biro birr birt bito bitt bitz bizz bobb bobi bobo boi- boii boit boob boor boot booz bor- bori boro borr bort borz botb boti boto bott bozi bozo brio brit briz brob broo bror brot broz brrr btob btor btrt bttb bzzt bzzz ibot ibri ibro ibtb iiii iiio iiit iioi iioo iitr iitt iobi ioii ioio ioit iooi iooo iori ioto iri- irio irob irri irti itoi itoo itor itri itto izzo obbo obit oboi obor obot obri obro oiii oirt oiti oitz oobi oooo oort ootb oozi orbb orbi orbo ori- orio orit oro- oror orot oroz orri orro orto orzo otit oto- otoo otor otro otti otto otzi rbbb rbbr rib- ribo riot rioz riri riti rito ritt ritz rizi rizz rob- robb robi robo robt roio roir roit roiz roob rooi roor root rooz rori roro rort roti roto rotr rott rozi rozz rrrr tbit tbrb tibi tiit tirb tiri tiro tirr titi tito titt titz tizi tizz tobi tobo tobt toit toor toot tori toro torr tort toti toto totr tott tozo tri- trib trio trit triz troi troo trot trtr ttbb tttt tzzt z-ro zibo ziri ziro ziti zito zizi zizz zobo zoio zoo- zoot zorb zori zoro zort zoti zott zotz zozo zzzz