A sphere
The theorem of classification of the surfaces states that any compact, connected, orientable surface without boundary can be related to a standard surface. We can visualize these standard surfaces as spheres with some handles attached or, otherwise, as doughnuts with a certain number of holes. The sphere can be considered as the basic stage of both constructions (being zero the number involved). When the number becomes 1, we get the torus in the shape of the sphere with one handle or the doughnut with one hole.
© matematita
The image belongs to the sections...:
The sphere (Topology)
Standard surfaces (Topology)
Sphere (3D geometry)
