Periodic Tesselations with Flat Surfaces

[lkuna24]

To create a tesselation/mesh such that the resulting structure is still a square/cube with flat surface but has periodicity. To elaborate, the +z face of the cube it would be exactly the same as the -z face, and for all the sides etc.
Resulting cube would have tesselations periodic across all faces.

[rquey]

The reason why non-cubic periodic tessellations have been preferred is that cells are not cut, and therefore there is no additional surfaces, etc. This is easier for generation, regularization (although it is not implemented yet) and meshing. Moreover, and from a general point of view, this should not cause problems from the solver side - the loading just has to be defined a little differently. (Complain if I am wrong.)