makeRectangularPreviousConn() {
    const width = this.NOTCH_WIDTH;
    const height = this.NOTCH_HEIGHT;

    /**
     * Since previous and next connections share the same shape you can define
     * a function to generate the path for both.
     * @param {number} dir Multiplier for the horizontal direction of the path (-1 or 1)
     * @returns {Object} SVGPath line for use with previous and next connections.
     */
    function makeMainPath(dir) {
      return Blockly.utils.svgPaths.line([
        Blockly.utils.svgPaths.point(0, height),
        Blockly.utils.svgPaths.point(dir * width, 0),
        Blockly.utils.svgPaths.point(0, -height),
      ]);
    }
    const pathLeft = makeMainPath(1);
    const pathRight = makeMainPath(-1);

    return {
      width: width,
      height: height,
      pathLeft: pathLeft,
      pathRight: pathRight,
    };
  }
@returns {Object} Rectangular notch for use with previous and next connections.