The question is not clear.
Hardest, as in the most rigid, is a triangular prism (or tetrahedron).
Hardest, to work the geometry of, is probably an irregular blob.
Many 3d shapes have a corner.
A 12 sided 3D shape is a dodecahedron.
A tridekahedron is a 3D 30 sided shape.
A 3D shape that has 6 edges is called a hexagonal prism.
it is a strong inadiquate word that describes a 3d shape. A tetrahedron.
A dodecahedron
It depends on the 3d shape.
It is not a 3D shape.
A camera is a 3D shape. A photograph is a 2D projection of a 3D shape onto a 2D shape.
a pyramid is a 3D shape :)
is a square a 3d shape
what 3d shape is a tyre
A sheet ( piece) of paper is a 3 - dimensional object. The length and width can be measured with a ruler. However, the thickness (3rd dimension) you will need a micrometer to measure the thickness. As a solid object it is a 'cuboid'.
Many 3d shapes have a corner.
A 3d shape can have infinite sides
A 12 sided 3D shape is a dodecahedron.
A cylinder is a 3d shape because you can see the in side of it.