bbb bbd bbe bbi bbx bdb bdd bde bdi bdx be- beb bed bee bei bex bi- bib bid bie bii bix bxb bxd bxi bxx dbb dbd dbe dbi dbx ddb ddd dde ddi ddx de- deb ded dee dei dex di- dib did die dii dix dxd dxi dxx ebb ebd ebe ebi ebx ed- edb edd ede edi edx eeb eed eee eex eib eid eie eii eix ex- exd exe exi exx i-d ibb ibd ibe ibi ibx idb idd ide idi idx ie- ied iee iei iex iib iid iie iii iix ixe ixi xbe xbx xdb xde xdi xed xee xex xie xii xix xxi xxx