{
  "spec": {
    "data": {"url": "data/cars.json"},
    "mark": "?",
    "encodings": [
      {
        "channel": "?",
        "field": "Cylinders",
        "type": "ordinal"
      },{
        "channel": "?",
        "bin": "?",
        "aggregate": "?",
        "field": "Horsepower",
        "type": "quantitative"
      }
    ]
  },
  "groupBy": ["field", "aggregate", "bin", "timeUnit", "stack"],
  "chooseBy": "effectiveness",
  "config": {
    "autoAddCount": true
  }
}