axis1.vl

{
    "mark": "line",
    "data": {
        "values": [
            {
                "x": 0,
                "order": 1,
                "y": 1000
            },
            {
                "x": 1000,
                "order": 2,
                "y": 1000
            },
            {
                "x": 1000,
                "order": 3,
                "y": 0
            },
            {
                "x": 0,
                "order": 4,
                "y": 0
            },
            {
                "x": 0,
                "order": 5,
                "y": 1000
            },
            {
                "x": 1000,
                "order": 6,
                "y": 0
            }
        ]
    },
    "$schema": "https://vega.github.io/schema/vega-lite/v4.json",
    "encoding": {
        "x": {
            "field": "x",
            "type": "quantitative",
            "axis": null
        },
        "order": {
            "field": "order",
            "type": "ordinal"
        },
        "y": {
            "field": "y",
            "type": "quantitative",
            "axis": null
        }
    }
}