[Tutor] rotation within arrays

[Andy Cheesman]

Dear People,

I wondering if any of you lovely people can make a suggestion on a
problem which I have with a n dimensional array.
For example, I've a 3x3 array and I have been mapping an element from 1D
to the one directly above it. 3->12

0 1 2
3 4 5
6 7 8

 9 10 11
12 13 14
15 16 17

The problem which I have is that I now need to rotated alternative layer
of the arrays but I still need to have the original mapping i.e 3 -> 12.

0 1 2
3 4 5
6 7 8

11 14 17
10 13 16
 9 12 15

Does anyone have any suggestions for how to do this?

Thanks

Andy