code: function () {
      if (this.data instanceof SAT.Circle) {
        this.displayAttrs.cx = this.data.pos.x;
        this.displayAttrs.cy = this.data.pos.y;
        this.displayAttrs.r = this.data.r;
      } else {
        this.displayAttrs.path = poly2path(this.data);
      }
      this.display.attr(this.displayAttrs);
    }
docs: Call this to update the display after changing the underlying data.