Loess regression

<Plot grid>
    <Dot
        data={cars}
        y="weight (lb)"
        x="power (hp)"
        symbol="plus"
        opacity={0.6} />
    <RegressionY
        data={cars}
        type="loess"
        {span}
        stroke="var(--svp-red)"
        x="power (hp)"
        y="weight (lb)" />
</Plot>