bbbb bbeb bebb bebe bebo beeb beef beer befe beff befo beo- beof beor bere bero berr bobb bobe bobo boee boef boeo boer bofe boff boob booe boof boor bor- bore borf boro borr breb bree bref breo brer brob broe broo bror brrr ebbo ebbr eber eboe eboo ebor ebro eeee eefe eero efbr efeo efor eore erbb erbe ereb erer erob eroe eroo erre erro febo feeb feer fefe feff fefo feof ferb fere fero ferr ffee ffff ffrr foer fofo foof for- forb fore foro forr free freo frob froe o-eo obbo ober oboe obor obre obro oere ofer off- offe offo offr ofor ofre oobe ooer ooff oooo oore orbb orbe orbo ore- oreb oreo orer orfe orff oro- oroe orof oror orro rbbb rbbr rebb rebe rebo reeb reef refe reff refr reof rere rero rfef rob- robb robe robo roer rofe roff rofo roob roof roor rore roro rrrr