-ol bbb bbc bbl bbo bbx bcb bcc bcl bco bcx blb blc bll blo blx bob boc bol boo box bxb bxl bxo bxx c-- cbb cbc cbl cbo cbx ccb ccc ccl cco ccx cl- clb clc cll clo clx co- cob coc col coo cox cxc cxl cxo cxx lbb lbc lbl lbo lbx lcb lcc lcl lco lcx llb llc lll llo lob loc lol loo lox lxc lxo lxx ob- obb obc obl obo obx oc- ocb occ ocl oco ocx olb olc oll olo oo- oob ooc ool ooo oox ox- oxb oxc oxo oxx xbc xbl xbx xcb xcl xcx xlb xoc xoo xox xxl xxo xxx