motif
3-dimensional
solid shapes are 3-D
A hexagon is a 2-dimensional shape. A "structure" implies a 3-dimensional shape but you have not specified whether it is a hexagonal pyramid, a hexagonal prism or some other shape that is [partly] based on a hexagon. Without that information it is not possible to give a more helpful answer.
yes,it is 3 dimensional
Yes, it is a 3d cubic structure, joints are orthogonal; Unlike a 2d structure such as a thin wafer of salt NaCl which because of its lattice structure, can form perfectly flat planes.
Examples of 3 dimensional structure are a pyramid, a cone, a cylinder, a prism, a cuboid ... etc
In an operating system a layered structure is composed of a kernel, some servers, and some user level libraries. All of these put together are a layered structure.
Tertiary Structure.....:)
That depends on where the forces will be coming from. If both structures are subjected to forces in 3 dimensions, then the 3 dimensional structure will be less apt to fall over or something. If by strength you mean not compressing, then the 2 dimensional structure might be better theoretically, though you couldn't really build a 2 dimensional structure.
motif
In an operating system a layered structure is composed of a kernel, some servers, and some user level libraries. All of these put together are a layered structure.
The atmospheric structure of the environment is layered.
A crystal lattice.
What is the Lattice Structure
Diamond
Terrestrial Planets