eee eeo ees eet eex eo- eoe eoo eos eot es- ese eso ess est esx ete eto ets ett etx ex- exe exo exs ext exx oee oeo oes oet oex oo- ooo oos oot oox os- ose oso oss ost osx ot- ote oto ots ott ox- oxo oxt oxx se- see seo ses set sex soe soo sos sot sox ss- sse sso sss sst ssx ste sto sts stt stx sxs sxt t-x te- tee teo tes tet tex to- toe too tos tot tox tse tso tss tst tsx tte tto tts ttt ttx txe txs txt xee xes xet xex xoo xos xot xox xss xst xts xtx xxo xxx