-er bbb bbd bbe bbo bbr bbt bbx bdb bdd bde bdo bdr bdt bdx be- beb bed bee beo ber bet bex bob bod boe boo bor bot box brb brd bre bro brr brt brx btb btd bte bto btr btt btx bxb bxd bxo bxx dbb dbd dbe dbo dbr dbt dbx ddb ddd dde ddo ddr ddt ddx de- deb ded dee deo der det dex dob dod doe doo dor dot dox drb drd dre dro drr drt drx dtb dtd dte dto dtr dtt dtx dxd dxo dxr dxt dxx ebb ebd ebe ebo ebr ebt ebx ed- edb edd ede edo edr edt edx eeb eed eee eeo eer eet eex eo- eob eod eoe eoo eor eot erb erd ere ero err ert etb etd ete eto etr ett etx ex- exd exe exo exr ext exx ob- obb obd obe obo obr obt obx odb odd ode odo odr odt oeb oed oee oeo oer oet oex oo- oob ood ooo oor oot oox or- orb ord ore oro orr ort orx ot- otb otd ote oto otr ott ox- oxb oxo oxt oxx rbb rbd rbe rbo rbr rbt rbx rdb rdd rde rdo rdr rdt rdx re- reb red ree reo rer ret rex rob rod roe roo ror rot rox rrb rrd rrr rrt rtb rtd rte rto rtr rtt rtx rxr t-x tbb tbd tbe tbo tbr tbt tdb tdd tde tdo tdr tdt tdx te- teb ted tee teo ter tet tex to- tob tod toe too tor tot tox trb trd tre tro trr trt trx ttb ttd tte tto ttr ttt ttx txe txt xbe xbr xbx xdb xde xdr xdt xed xee xer xet xex xod xoo xor xot xox xrd xrt xrx xtr xtx xxo xxx