bbbb bblb blno blob blon bloo blou blub blur bnor bnrr bobb bobo bobu boll boln bolo bolu bonn bono bonu boob bool boon boor bor- born boro borr boru boul boun bour brno brob brol bron broo bror brou brrr brun bubb bubo bubu bulb bull bulu bunb bunn buno bunu buol buon bur- burb burl burn buro burr buru lblr llll lloo lob- lobb lobo loll lolo lono lonr loob lool loon loor lorn loro loul loun lour louu lron lrrr lull lulu lunn luno nbbo nlrb nnnn nobo nobu noll nolo non- nonn nono nonu noo- noob nool noon nooo noor nor- norb norn noro norr noul noun nour nrlb nron nrrl nubl null nunn nuno nuon nurl nurn nurr nuru obbo oblu obol obon obor obro olbo ollo olon olor olur onno onon onor onur oolo oooo orbb orbo orbu orlo orlu orno oro- oron oror orro orub oulu oun- our- ourn ouro ouu- rbbb rbbr rnbr rob- robb robo robu roll rolo rono roob rool roon roor roro roru roub roul roun rrrr rrun rubb rubu rull rulo runn runo ruro ruru ruun ubbo ublo ubon ullo ullr ulno ulo- ulul unno unon unro uor- uro- urol uroo urun urur uulu uuno uuuu