stroke {
  child: linear-gradient {
    bounds: 45 45 210 110;
    start: 50 50;
    end: 50 150;
    stops: 0 rgb(255,0,0), 0 rgb(255,255,0), 1 rgb(255,255,0), 1 rgb(0,0,255);
    premultiplied: false;
  }
  path: "\
M 50 50 h 200 v 100 h -200 z";
  line-width: 10;
  line-cap: butt;
  line-join: miter;
}