bbbb bbdd bblb bd-r bdii bibb bibi bibl bidi bidr bidu bild bili bill bilu birb bird biri birl birr biru bldr blir blub blud blur brid bril brrr brud bubb bubi bubu budb budd budi budl budu buid buir buiu bulb buld buli bull bulu bur- burb burd buri burl burr buru dddd ddub dibb didi didu diii dili dill dird dirl dirr dlbd dlib dlii dlil drib dril drub drui druu dub- dubb dubu dudd dudu duid duil duir duli dull dulu duri duru duul duur ibid ibrd ibri idid idil idir idli idub iiii ilir ill- illd illi ilud iri- irid iril irlb irri irul iuiu lblr libr libu lidb lidl liii liir lilb lili lill lilu lird liri lirl lirr liru lldb llll llud lrdd lrrr ludd ludi luli lull lulu lurd luri rbbb rbbr rib- ribu ridd ridi rill rilu riri rrrr rubb rubi rubu rudd rudi rudl ruid rull rurd ruri ruru ruud ubbi ubid ubii ubir ubli ubud uddi udid udir uirr ulli ullr ulul urbi urdu urib uriu urri urur uulu uuri uuuu