bbb bbc bbo bbr bbx bby bcb bcc bco bcr bcx bcy bob boc boo bor box boy brb bro brr brx bry bxb bxo bxx by- byc byo byr c-- cbb cbc cbo cbr cbx cby ccb ccc cco ccr ccx co- cob coc coo cor cox coy crb crc cro crr crx cry cxc cxo cxr cxx cyb cyc cyo cyr ob- obb obc obo obr obx oby oc- ocb occ oco ocr ocx oo- oob ooc ooo oor oox or- orb orc oro orr orx ory ox- oxb oxc oxo oxx oxy oyo rbb rbc rbo rbr rbx rcb rcc rco rcr rcx rob roc roo ror rox roy rrb rrc rrr rxr ry- ryc ryo ryr ryy xbc xbr xbx xcb xcr xcx xoc xoo xor xox xrc xrx xry xxo xxx xxy xyr xyy ybc ybr yby ycc yco ycy yob yoc yoo yor yox yoy yrc yro yxy yyb yyc yyy