{
    "title": "positions or labels",
    "$schema": "http://json-schema.org/draft-04/schema#",
    "type": "array",
    "items": {
        "anyOf": [
            {
                "description": "Actually, each even item is a string, each odd item is an integer",
                "type": "array",
                "minItems": 1,
                "items": {
                    "anyOf": [
                        {
                            "type": "integer"
                        },
                        {
                            "type": "string"
                        }
                    ]
                }
            },
            {
                "type": "string"
            }
        ]
    }
}