-ol bbb bbe bbl bbo bbt be- beb bee bel beo bet blb ble bll blo blt bob boe bol boo bot btb bte btl bto btt ebb ebe ebl ebo ebt eeb eee eel eeo eet elb ele ell elo elt eo- eob eoe eol eoo eot etb ete etl eto ett lbb lbe lbl lbo lbt leb lee lel leo let llb lle lll llo llt lob loe lol loo lot ltb lte ltl lto ltt ob- obb obe obl obo obt oeb oee oel oeo oet olb ole oll olo olt oo- oob ool ooo oot ot- otb ote otl oto ott tbb tbe tbl tbo tbt te- teb tee tel teo tet tle tll tlo tlt to- tob toe tol too tot ttb tte ttl tto ttt