vector > matrix > box > ?

[Vegan]

I was puzzling about a box template for the library which is the next tensor up from a matrix

typically i use nested std::vector as the container

now a box object would have rows, columns and depth

what about the perspective, there is rotational considerations

a vector could be taken from any of 3 sides?

and a matrix slice?

any convention as to the usual matrix[x][y][z]

of course this becomes insane moving beyond a box