code: function() {
      this.jsonInit({
        "message0": Blockly.Msg.SENSING_OF,
        "args0": [
          {
            "type": "field_dropdown",
            "name": "PROPERTY",
            "options": [
              [Blockly.Msg.SENSING_OF_XPOSITION, 'x position'],
              [Blockly.Msg.SENSING_OF_YPOSITION, 'y position'],
              [Blockly.Msg.SENSING_OF_DIRECTION, 'direction'],
              [Blockly.Msg.SENSING_OF_COSTUMENUMBER, 'costume #'],
              [Blockly.Msg.SENSING_OF_COSTUMENAME, 'costume name'],
              [Blockly.Msg.SENSING_OF_SIZE, 'size'],
              [Blockly.Msg.SENSING_OF_VOLUME, 'volume'],
              [Blockly.Msg.SENSING_OF_BACKDROPNUMBER, 'backdrop #'],
              [Blockly.Msg.SENSING_OF_BACKDROPNAME, 'backdrop name']
            ]
          },
          {
            "type": "input_value",
            "name": "OBJECT"
          }
        ],
        "output": true,
        "category": Blockly.Categories.sensing,
        "outputShape": Blockly.OUTPUT_SHAPE_ROUND,
        "extensions": ["colours_sensing"]
      });
    }
docs: Block to report properties of sprites.
  @this Blockly.Block