-ol bbb bbc bbl bbo bbs bcb bcc bcl bco bcs blb blc bll blo bls bob boc bol boo bos bsb bsc bsl bso bss c-- cbb cbc cbl cbo cbs ccb ccc ccl cco ccs cl- clb clc cll clo cls co- cob coc col coo cos csb csc csl cso css lbb lbc lbl lbo lbs lcb lcc lcl lco lcs llb llc lll llo lls lob loc lol loo los lsb lsc lsl lso lss ob- obb obc obl obo obs oc- ocb occ ocl oco ocs olb olc oll olo ols oo- oob ooc ool ooo oos os- osb osc osl oso oss sbb sbc sbl sbo sbs scb scc scl sco scs slb slc sll slo sls sob soc sol soo sos ss- ssb ssc ssl sso sss