> ijk for indices in loops are actually clearer than random names in nested loops precisely because it is a very common convention and because they occur in a defined order. So you always know that "j" is the second nesting level, for instance. Which relates to the visual layout of the code.

In problem domains that emphasize multidimensional arrays, yes.

More often nowadays I would see `i` and think "an element of some sequence whose name starts with i". (I tend to use `k` and `v` to iterate keys and values of dictionaries, but spell `item` in full. I couldn't tell you why.)