“…By means of mathematical or computer method, these isotopic links could be removed or filtered out [37,38,40] . After removing the isotopic links, 6 unique types of DNA triangular bipyramids remain, showed in Table 2, and 16 triangular bipyramids are classified into six groups:{{1}, {2, 15}, {3, 5, 10}, {4, 6, 8, 9, 11, 13}, {7, 12, 14}, {16}} [38] . 6 Intuitively, with the increase of edges with odd half-twists, the number of strands to construct triangular bipyramid decreases.…”