facet4.vl

{
    "$schema": "https://vega.github.io/schema/vega-lite/v4.json",
    "data": {
        "url": "https://vega.github.io/vega-lite/data/cars.json"
    },
    "description": "Distributions of car engine power for different countries of origin",
    "encoding": {
        "row": {
            "field": "Origin",
            "title": "Origin facet",
            "type": "ordinal"
        },
        "x": {
            "bin": {
                "maxbins": 15
            },
            "field": "Horsepower",
            "type": "quantitative"
        },
        "y": {
            "aggregate": "count",
            "type": "quantitative"
        }
    },
    "mark": "bar"
}