Lineal oscilation thru bone rotation w/ variable stroke

[Genete]

Well, joining two springy mechanisms in a particular way, I can build a mecanism that can make a linear oscilation with variable stroke.
It will be used to perform elliptical rotation with variable length of the vertical and horizontal axis. It is a new step to try to make a 3D Y and X rotation of a shape (point) just projected to camera view.

Here the anme file.

In the file there are two unconstrained bones, a big one and a small one. The big one controls the overal traslation, the small bone controls the traslation stroke.

I think it could have more uses but for he moment I'm only investigating.

Thanks for your attention.