-ol bbb bbc bbd bbl bbo bcb bcc bcd bcl bco bdb bdc bdd bdl bdo blb blc bld bll blo bob boc bod bol boo c-- cbb cbc cbd cbl cbo ccb ccc ccd ccl cco cdb cdc cdd cdl cdo cl- clb clc cld cll clo co- cob coc cod col coo dbb dbc dbd dbl dbo dcb dcc dcd dcl dco ddb ddc ddd ddl ddo dl- dlb dlc dld dll dlo dob doc dod dol doo lbb lbc lbd lbl lbo lcb lcc lcd lcl lco ldb ldc ldd ldl ldo llb llc lld lll llo lob loc lod lol loo ob- obb obc obd obl obo oc- ocb occ ocd ocl oco odb odc odd odl odo olb olc old oll olo oo- oob ooc ood ool ooo