[trishume]

Yah mipmaps are an N-dimensional generalization of the breadth first layout of implicit aggregation, where the aggregation function is averaging.

It may in theory be possible to generalize the in-order layout I talk about in a similar way, but I'm not sure it would be that useful, maybe it would allow you to append rows or columns to your mipmapped image more easily, but I don't know of any applications where that's useful.