ddd ddo ddp dds ddt dod doo dop dos dot dpd dpo dpp dps dpt dsd dso dsp dss dst dtd dto dtp dts dtt odd odo odp ods odt oo- ood ooo oop oos oot op- opd opo opp ops opt os- osd oso osp oss ost ot- otd oto otp ots ott p-p pdd pdo pdp pds pdt pod poo pop pos pot ppd ppo ppp pps ppt ps- psd pso psp pss pst pt- ptd pto ptp pts ptt sdd sdo sdp sds sdt sod soo sop sos sot spd spo spp sps spt ss- ssd sso ssp sss sst std sto stp sts stt tdd tdo tdp tds tdt to- tod too top tos tot tpd tpo tpp tps tpt tsd tso tsp tss tst ttd tto ttp tts ttt