The singular points of an irreducible plane cubic curve are quite limited: one knot/node, or one cusp. Our research starts originally with the Descartes Folium, which has a knot/node, and is able to have many group structures. The original results are concentrated in six directions: (i) special structures on affine algebraic varieties, (ii) theory of K-groups, (iii) isomorphisms of K-groups, (i...