A sphere is more than just a set of directions, but that's all EuDX needs. As a rule of thumb, if a function would only use one attribute of an argument, I prefer to just pass that attribute so I like `f(a, b, sphere.vertices)` more than `f(a, b, sphere)` when it's possible. Peak finding for example cannot just work on vertices, it would need to be `pf(odf, vertices, edges, faces)` and that's obviously not what we want. That being said, I'm not strongly apposed to passing `sphere` to EuDX, but it would break existing code.