For anyone whose magnet related memories are not filled with various line illustrations of the forces, that’s probably it.
And even though my head is full of those illustrations, I don’t seem to understand how the iron fillings and ferrofluids make the shapes they do instead of just sticking to the magnet. And I am too lazy to do the maths to make myself understand.
Yeah that thing. Except that they were dubbed “magnetic lines of force”. Also, I remember it being separately explained that even though they were called that, they didn’t represent the direction of force (of course not, or you’d not need the right-hand-rule and left-hand-rule).
Looking at the iron shavings though, it seemed more like low potential energy regions/ stable regions.
Also it give a feeling of being analogous to fringe patterns.