{
    "$schema": "https://json-schema.org/draft/2020-12/schema",
    "$defs": {
        "item": {
            "type": "array",
            "items": false,
            "prefixItems": [
                { "$ref": "#/$defs/sub-item" },
                { "$ref": "#/$defs/sub-item" }
            ]
        },
        "sub-item": {
            "type": "object",
            "required": ["foo"]
        }
    },
    "type": "array",
    "items": false,
    "prefixItems": [
        { "$ref": "#/$defs/item" },
        { "$ref": "#/$defs/item" },
        { "$ref": "#/$defs/item" }
    ]
}

[
    [ {"foo": null}, {"foo": null} ],
    [ {"foo": null}, {"foo": null} ],
    [ {"foo": null}, {"foo": null} ]
]
  Failed: /0/0: False schema always fails
  Failed: /0/1: False schema always fails
  Failed: /1/0: False schema always fails
  Failed: /1/1: False schema always fails
  Failed: /2/0: False schema always fails
  Failed: /2/1: False schema always fails
  Failed: /0: False schema always fails
  Failed: /1: False schema always fails

