A sphere in Flatland
If an inhabitant of Flatland (the famous novel of Abbott) would see a sphere passing through its plane world, he could see only the curves obtained by sectioning the sphere with a plane: so, circumpherences that growth in dimension from a point to the radius of the sphere, and circumpherences that reduce their radius untill they disappear.
immagine di Gian Marco Todesco
The image belongs to the sections...:
Various matters (4D geometry)