a-a a-b a-t aaa aab aao aap aat aax ab- aba abb abo abp abt abx aoa aob aoo aop aot aox ap- apa apb apo app apt apx at- ata atb ato atp att atx ax- axa axo axp axt axx b-p baa bab bao bap bat bax bba bbb bbo bbp bbt bbx boa bob boo bop bot box bpa bpb bpo bpp bpt bpx bta btb bto btp btt btx bxb bxo bxx oaa oab oao oap oat oax ob- oba obb obo obp obt obx oo- ooa oob ooo oop oot oox op- opa opb opo opp opt opx ot- ota otb oto otp ott ox- oxa oxb oxo oxt oxx p-p paa pab pao pap pat pax pba pbb pbo pbp pbt pbx poa pob poo pop pot pox ppa ppb ppo ppp ppt ppx pt- pta ptb pto ptp ptt ptx pxt t-x taa tab tao tap tat tax tba tbb tbo tbp tbt to- toa tob too top tot tox tpa tpb tpo tpp tpt tpx tta ttb tto ttp ttt ttx txt xaa xap xat xbx xoa xoo xop xot xox xpa xpb xpo xpp xpt xtp xtx xxo xxp xxx