Any shape is mathematical.
No shape is mathematical really unless it has been created by a mathematical formula, but is certainly a geometric shape. But anything which is a 2D or 3D shape is geometric. My improvement: A catenary curve from a mathematical equation such as cosh x, is a mathematical and natural shape. Maby each other arch can be approximated by a mathematical formula.
The shape of a tin can is a cylinder.
It is a cube.cube
A torus is the mathematical term for a donut like shape.
A delta star is a mathematical technique to simplify the analysis of an electrical network, not a "real" star.A delta star is not a its a mathematical formulasee related link
It is a parallelepiped.
so a star is an shape