Faceted waffle

<Plot
    x={{
        type: 'band',
        tickFormat: (d) => d.getFullYear()
    }}>
    <WaffleY
        unit={10}
        {...groupX(
            {
                data: olympians,
                x: 'date_of_birth'
            },
            { y: 'count', interval: '5 years' }
        )} />
</Plot>