Faceted regression

Regression lines grouped by a categorical variable, with different colors for each group.

<Plot grid frame aspectRatio={1} inset={5}>
    <Dot
        data={penguins}
        x="culmen_length_mm"
        y="culmen_depth_mm"
        fill="#999"
        opacity={0.2} />
    <Dot
        data={penguins}
        x="culmen_length_mm"
        fx="species"
        y="culmen_depth_mm"
        fill="species" />
    <RegressionY
        data={penguins}
        x="culmen_length_mm"
        fx="species"
        y="culmen_depth_mm"
        stroke="species" />
</Plot>