bbbb bbrc bcbc bccc bcor bnoc bnor bnrr bobb bobo boco bonc bonn bono boob booc boon boor bor- born boro borr brcb brno brob broc bron broo bror brrr c-bo cbbc cbcc cbcn cbcr cbrn ccbc ccbn cccb cccc ccnb ccnc ccnr ccob ccoc ccrc cnbc cnco cnrc cnrr cobb cobo coco con- conc conn cono coob coon cor- corb corc corn coro corr crbc crcc crcr crob croc cron croo cror nbbc nbbo nbcc nbco ncbc nccc nccn nccr ncnc ncoc ncor ncrc nnnn nobc nobo noco non- nonn nono noo- noob noon nooo noor nor- norb norc norn noro norr nroc nron nrrc obbo obon obor obro ocbc occc occn ocon ocro ocrr onc- onco onno onon onor oocr oooo orbb orbo orco ornc orno oro- oron oror orro rbbb rbbr rcbc rcbo rccb rccc rcnr rcon rnbr rnco rob- robb robo rocc roco ronc rono roob roon roor rorc roro rrrr