Ah I was mistakeningly thinking clockwise means the number is going from low->high. Thanks.

If this is true:

We start with both rings aligned on 0 at the top, and on each move we spin each ring by 1.

The inner ring spins clockwise and the outer ring spins anti-clockwise

And assuming the rings are sequential, i.e. [0, 1, 2] and [0, 1, 2, 3].

Then why is this true:

e.g. if innerMax is 2 and outerMax is 3 then after
1 move: inner = 2, outer = 1

It says both start at 0. Wouldn't the above be:
1 move: inner = 1, outer = 3