Stacked doughnut charts

### Feature Proposal

Looking into ways to implement the following:

Useful when filters are applied to the original dataset. I'm unaware if this is currently possible. I'd be grateful for any pointers, possibly there is a plugin I could base this on?

### Possible Implementation

I can imagine implementing this if there exists a way to render a doughnut chart with overlayed arcs. When filters are applied, the bottom layer is made slightly transparent, the top layer arc segments get specific widths to illustrate different values.