bbb bbo bbr bbs bbt bbx bby bob boo bor bos bot box boy brb bro brr brs brt brx bry bsb bso bsr bss bst bsx bsy btb bto btr bts btt btx bty bxb bxo bxx by- byo byr bys byt ob- obb obo obr obs obt obx oby oo- oob ooo oor oos oot oox or- orb oro orr ors ort orx ory os- osb oso osr oss ost osx ot- otb oto otr ots ott ox- oxb oxo oxt oxx oxy oyo oys rbb rbo rbr rbs rbt rbx rob roo ror ros rot rox roy rrb rrr rrs rrt rsb rso rsr rss rst rsx rtb rto rtr rts rtt rtx rty rxr rxs ry- ryo ryr rys ryy sbb sbo sbr sbs sbt sbx sby sob soo sor sos sot sox soy sr- srb sro srr srs srt srx sry ss- ssb sso ssr sss sst ssx stb sto str sts stt stx sty sxs sxt sy- syb syr sys syt syx t-x tbb tbo tbr tbs tbt to- tob too tor tos tot tox toy trb tro trr trs trt trx try tsb tso tsr tss tst tsx tsy ttb tto ttr tts ttt ttx tty txs txt tyo tyr tys tyt xbr xbx xoo xor xos xot xox xrt xrx xry xsb xss xst xtr xts xtx xty xxo xxx xxy xyr xyy ybr ybs yby yob yoo yor yos yot yox yoy yro yrs yrt ysb yso ysr yss yst ysy yto ytr yts ytt yxy yyb yys yyt yyy