[
  [
    {
      "namespace": "signal",
      "name": "brush_x",
      "scope": [0],
      "value": [90.5, 295.3]
    }
  ],
  [
    {
      "namespace": "signal",
      "name": "click_tuple",
      "scope": [1],
      "value": {
        "unit":  "concat_1",
        "fields":  [{"field": "weather", "channel": "color", "type": "E"}],
        "values": ["rain"]
      }
    }
  ],
  [
    {
      "namespace": "signal",
      "name": "click_tuple",
      "scope": [1],
      "value": {
        "unit":  "concat_1",
        "fields":  [{"field": "weather", "channel": "color", "type": "E"}],
        "values": ["sun"]
      }
    }
  ],
  [
    {
      "namespace": "signal",
      "name": "brush_x",
      "scope": [0],
      "value": [0, 0]
    }
  ]
]