code: function() {
      this.jsonInit({
        "message0": Blockly.Msg.DATA_SHOWVARIABLE,
        "args0": [
          {
            "type": "field_variable",
            "name": "VARIABLE"
          }
        ],
        "previousStatement": null,
        "nextStatement": null,
        "category": Blockly.Categories.data,
        "colour": Blockly.Colours.data.primary,
        "colourSecondary": Blockly.Colours.data.secondary,
        "colourTertiary": Blockly.Colours.data.tertiary
      });
    }
docs: Block to show a variable
  @this Blockly.Block