Maybe less readable than I remembered, sorry! But these `CartesianIndex` things are how you index multi-dimensional arrays.

If by indexing you only mean adding offsets to pointers with your bare hands, this is possible but discouraged. Because you'll produce a buggier and less general version of exactly what already exists. In this case, reversing an N-dimensional array, along any M of its axes, with arbitrary offsets -- there are a lot of ways to get that wrong.

What I mean is something like this:

    # one dimensional
    a = [1, 2, 3]
    # prints the number 1 @ index 0
    print(a[0])
    
    # multi-dimensional
    b = [[1, 2, 3], [4, 5, 6]]
    # prints the number 4 @ index (1, 0)
    print(b[1][0])

In Julia these indexes would start from 1. It doesn't seem like `CartesianIndex` solves this, since looking at some examples you still have to specify array indexes (Which start from 1): https://docs.julialang.org/en/v1/base/arrays/#Base.Iterators...

OK, I thought you were advocating zero based on complicated index calculations for some algorithm, with mod & div, which is what I was trying to say could be abstracted away. The literal syntax `a=[1,2,3]` makes a one-dimensional `Array{Int,1}` whose first element is indeed `a[1]`. (`b` is an array of arrays, while `c = [1 2 3; 4 5 6]` is an honest 2-dimensional array.)