bbbb bbdd bbdo bd-r bdii bibb bibi bibo bidi bido bidr bio- bioi biot birb bird biri biro birr birt bitd bito bitt bobb bobi bobo bodb bodi bodo boi- boid boii boit boob bood boor boot bor- bord bori boro borr bort botb botd boti boto bott brdo brdt brid brio brit brob brod broo bror brot brrr btdt btob btor btrt bttb d-bo dbit dbtt dddd ddot dibb dibo didi dido diii dior diot dird dirr dirt diti dito ditt dobb dobi dod- dodd dodi dodo doid doit doob dood door doot dord dori doro dorr dort dotd doti doto dott drib drit drob drod drot dtor dtot ibdo ibid ibot ibrd ibri ibro ibtb iddo idid idio idir idro iiii iiio iiit iioi iioo iitr iitt iobi iod- iodd iodo ioii ioio ioit iooi iooo iori ioto irdo iri- irid irio irob irod irri irti itdo itoi itoo itor itri itto obbo obdt obid obit oboi obor obot obri obro obtd odbo oddd oddi odio odir odoo odor odot oido oiii oirt oiti oobi oodi ooid oooo oord oort ootb orbb orbi orbo ordo ori- orid orio orit oro- oror orot orri orro orto otbd otit oto- otoo otor otro otti otto rbbb rbbr rdio rib- ribo ridd ridi rido riot riri riti rito ritt rob- robb robi robo robt rodd rodi rodo roid roio roir roit roob rood rooi roor root rori roro rort roti roto rotr rott rrrr rtdt tbit tbrb tddb tdor tdri tibi tidd tiit tirb tird tiri tiro tirr titi tito titt tobi tobo tobt todd todi todo todt toid toit tood toor toot tord tori toro torr tort totd toti toto totr tott tri- trib trio trit trod troi troo trot trtr ttbb tttt