More 3D shapes and shape nets

There are lots of different types of solid shapes or figures.  We’ve already looked at 3-dimensional figures like cubes and prisms.  But there are also other ones, such as spheres (shaped like a tennis ball), cones (shaped like an ice cream cone) and pyramids (shaped like the Pyramids in Egypt).

People like to classify these solid figures into different groups.  One intuitive way of classifying different solid shapes is to group them based on whether all their faces or surfaces are flat.  For instance, a cube has six faces, all of which are flat squares.  But a sphere only has one surface, and it’s curved.

If you want to split solid shapes into more categories, you can further divide the flat and curved surface groups.  The flat faces group can be divided into prisms, pyramids or other polyhedra (plural of polyhedron) groups.  A polyhedron is a solid shape with many different plane faces, so it’s the general name for all the shapes in the flat face group.

The curved surface group can be divided up into shapes that only have curved surfaces, such as a sphere, and shapes that have a mixture, like cones and cylinders.