bbb bbc bbd bbo bby bcb bcc bcd bco bcy bdb bdc bdd bdo bdy bob boc bod boo boy by- byc byd byo c-- cbb cbc cbd cbo cby ccb ccc ccd cco cdb cdc cdd cdo cdy co- cob coc cod coo coy cyb cyc cyd cyo dbb dbc dbd dbo dby dcb dcc dcd dco ddb ddc ddd ddo ddy dob doc dod doo doy dy- dyb dyc dyd dyo dyy ob- obb obc obd obo oby oc- ocb occ ocd oco odb odc odd odo oo- oob ooc ood ooo oyd oyo ybc yby ycc ycd yco ycy ydo ydy yob yoc yod yoo yoy yyb yyc yyy