820 dots, arranged by a layout the chart does not ship

One dot per 10 million people, coloured by drinking water access. The droplet is a custom layout: a plain function that receives every mark and the plot rect and returns positions. Switch views and the same dots re-form, keeping their identity and colour, rather than being rebuilt.

Any silhouette works the same way, which is how a projection can supply the positions later without the chart engine changing.