a-be a-do aaaa aaab aaad aaae aaba aabb aabd aada aade aaea aaoe aaoo abaa abab abad abae abb- abba abbb abbe abbo abda abdo abed abee aboa abob abod aboo adaa adab adad adae adao adba adda addd adde addo adea adeb adee adeo adob adod adoe adoo aede aoba baaa baad baba babb babe babo bada badb badd bade bado baed bbad bbbb bbdd bbdo bbeb bead beba bebb bebe bebo beda bede bedo beeb beed beo- beod boab boad boba bobb bobe bobo boda bodb bode bodo boea boee boeo boob bood booe d-bo daab daad daae daba dabb dabo dada dade dado daeb dddd dead deae deba debe deda dedd dede dedo deeb deed doab doae doba dobb dobe dod- doda dodd dode dodo doea doob dood eaba eada eadb eadd ebba ebbo ebed eboe eboo edad edda edde eddo ede- edea edod eede eeea eeee eode o-eo oade obad obba obbo obea obed oboe odbo odda oddd odea oded odeo odoo oedo ooaa ooba oobe ooda oooo