a-do aaaa aaab aaad aaba aabb aabd aada aadu aaoo abaa abab abad abau abb- abba abbb abbo abda abdo abdu aboa abob abod aboo abou abua abud adaa adab adad adao adba adda addd addo addu adob adod adoo adua adub aoba auaa audo baaa baad baba babb babo babu bada badb badd bado badu bau- baud bbad bbau bbbb bbdd bbdo boab boad boba bobb bobo bobu boda bodb bodo bodu boob bood boua boud buad buba bubb bubo bubu buda budb budd budo budu d-bo daab daad daau daba dabb dabo dabu dada dado dadu daou daub daud dddd ddub doab doba dobb dobu dod- doda dodd dodo doob dood doub doud duaa duab duad dub- duba dubb dubu duda dudd dudo dudu duo- oaau obad obba obbo odbo odda oddd odoo odou ooaa ooba ooda oooo ouad ouu- uaua ubba ubbo ubod ubud udaa udad udau udoo uuuu