code: function (x, y, r) {
  		var attr = isObject(x) ?
  			x :
  			{
  				x: x,
  				y: y,
  				r: r
  			};
  
  		return this.createElement('circle').attr(attr);
  	}
docs: Draw and return an SVG circle
  @param {Number} x The x position
  @param {Number} y The y position
  @param {Number} r The radius