color {
  bounds: 0 0 150 50;
  color: rgb(0,0,0);
}
clip {
  clip: 50 0 50 50;
  child: cross-fade {
    progress: 0.6;
    start: color {
      bounds: 0 0 50 50;
      color: rgb(255,0,0);
    }
    end: color {
      bounds: 100 0 50 50;
      color: rgb(0,0,255);
    }
  }
}