The answer to the question depends on what measure of efficiency you are looking for. In terms of stability, a sphere is less efficient since it can roll away!
There Isn't a shape bigger than the Icosahedron.
A dodecahedron
A shape that has more faces than an octahedron (which has 8 faces) but fewer faces than an icosahedron (which has 20 faces) is a dodecahedron. A dodecahedron has 12 faces, satisfying the condition of having more than 8 and fewer than 20 faces.
The size comparison between an icosahedron and a cube depends on their specific dimensions, such as edge lengths or volumes. An icosahedron has a more complex shape with 20 triangular faces, while a cube has 6 square faces. Generally, for equal edge lengths, the cube will have a larger volume than the icosahedron. However, without defined dimensions, it's not possible to say definitively which is "bigger."
A nonagon (9 sides) for example.
Icosahedron can be bigger
It has flat sides to balance on, a sphere just rolls around.
There are several but there is one that comes to mind that has 20 congruent triangular faces called an icosahedron.
A sphere.
Apples are more efficient than coffee in this case.
Yes. Bird lungs are more efficient than mammal lungs.
Gas central heating is more efficient than electric.Open cast mining can be more efficient than deep mines.