bbbb bbfn bblb bffl blno blob blon bloo blou blub bluf blur bnor bnrr bobb bobo bobu boff bofu boll boln bolo bolu bonn bono bonu boob boof bool boon boor bor- borf born boro borr boru bouf boul boun bour brfu brno brob brol bron broo bror brou brrr brun bubb bubo bubu buff bufo bufr bulb bull bulu bunb bunn buno bunu buol buon bur- burb burl burn buro burr buru ffff ffrr ffun flnb flob flon floo flor flou flub fluf fluo flur fnuf fofo foll folo folr fono foof fool foon for- forb forl forn foro forr foul foun four frob frol fron frou frub frun fubb fubu fuff fufu full fulu funf fuor fur- furl furn furo furr lblr llll lloo lob- lobb lobo loff lofn loll lolo lono lonr loob loof lool loon loor lorn loro loul loun lour louu lron lrrr luff lufu lull lulu lunn luno nbbo nbfl nbuf nfff nfon nlrb nnnn nobo nobu nolf noll nolo non- nonn nono nonu noo- noob nool noon nooo noor nor- norb norf norn noro norr noul noun nour nrlb nron nrrl nubl nuff null nunn nuno nuon nurl nurn nurr nuru obbo oblu obol obon obor obro off- offo offr offu ofno ofor olbo ollo olof olon olor olur onlf onno onon onor onur ooff oolo oooo orbb orbo orbu orff orfu orlo orlu orno oro- orof oron oror orro orub ouff oulu oun- our- ourn ouro ouu- rbbb rbbr rffl rnbr rob- robb robo robu roff rofl rofo rolf roll rolo rono roob roof rool roon roor roro roru roub rouf roul roun rrrr rrun rubb rubu ruff rufo rull rulo runf runn runo ruro ruru ruun ubbo ublo ubon ullo ullr ulno ulo- ulul unlf unno unon unrf unro uofl uofo uor- urff uro- urol uroo urun urur uulu uuno uuuu