mask {
  source: color {
    bounds: 0 0 50 50;
    color: rgb(255,0,0);
  }
  mask: color {
    bounds: 0 0 50 50;
    color: rgba(204,204,204,0.666667);
  }
}
mask {
  mode: luminance;
  source: color {
    bounds: 50 0 50 50;
    color: rgb(255,0,0);
  }
  mask: color {
    bounds: 50 0 50 50;
    color: rgba(204,204,204,0.666667);
  }
}
mask {
  mode: inverted-alpha;
  source: color {
    bounds: 0 50 50 50;
    color: rgb(255,0,0);
  }
  mask: color {
    bounds: 0 50 50 50;
    color: rgba(204,204,204,0.666667);
  }
}
mask {
  mode: inverted-luminance;
  source: color {
    bounds: 50 50 50 50;
    color: rgb(255,0,0);
  }
  mask: color {
    bounds: 50 50 50 50;
    color: rgba(204,204,204,0.666667);
  }
}