abba[8], baba[8], abbo[8], babo[8], boba[8], obab[8], bada[7], doba[7],
bab[7], bob[7], bad[6], dba[6], bod[6], abo[5], boa[5], oba[5], dao[4], oda[4], deo[4], ode[4],
ba[4], be[4], bo[4], ad[3], da[3], de[3], do[3], od[3], aa[2], eo[2],
