-ol bbb bbc bbk bbl bbo bbx bcb bcc bck bcl bco bcx bkb bkc bkk bkl bko bkx blb blc blk bll blo blx bob boc bok bol boo box bxb bxl bxo bxx c-- cbb cbc cbk cbl cbo cbx ccb ccc cck ccl cco ccx ckb ckc cko ckx cl- clb clc clk cll clo clx co- cob coc cok col coo cox cxc cxk cxl cxo cxx kbb kbc kbk kbl kbo kbx kcb kcc kck kcl kcx kkb kkc kkk kkl kl- klb klc klo klx kob koc kok kol koo kxl kxo lbb lbc lbk lbl lbo lbx lcb lcc lck lcl lco lcx lkb lkl llb llc llk lll llo lob loc lok lol loo lox lxc lxo lxx ob- obb obc obk obl obo obx oc- ocb occ ock ocl oco ocx okb okc okk okl oko olb olc olk oll olo oo- oob ooc ook ool ooo oox ox- oxb oxc oxo oxx xbc xbl xbx xcb xcl xcx xkb xkl xlb xoc xok xoo xox xxl xxo xxx