function createOutline(gfx) {
    var outline = svgCreate('rect');

    svgAttr(outline, assign({
      x: 0,
      y: 0,
      rx: 4,
      width: 100,
      height: 100
    }, OUTLINE_STYLE));

    return outline;
  }
@param {SVGElement} gfx

@return {SVGElement} outline