It's common to use double letters (ii, jj, kk) as inner indices when writing tiled multi-dimensional array code. Regardless of whether you think that is a good

It's common to use double letters (ii, jj, kk) as inner indices when writing tiled multi-dimensional array code. Regardless of whether you think that is a good convention, you should be preserving that convention if you are editing legacy code that was written that way.