c-- ccc cco ccr cct co- coc coo cor cot coy crc cro crr crt cry ctc cto ctr ctt cty cyc cyo cyr cyt oc- occ oco ocr oct oo- ooc ooo oor oot or- orc oro orr ort ory ot- otc oto otr ott oyo rcc rco rcr rct roc roo ror rot roy rrc rrr rrt rtc rto rtr rtt rty ry- ryc ryo ryr ryy tcc tco tcr tct to- toc too tor tot toy trc tro trr trt try ttc tto ttr ttt tty tyc tyo tyr tyt ycc yco ycy yoc yoo yor yot yoy yrc yro yrt ytc yto ytr ytt yyc yyt yyy