<!DOCTYPE html><!-- webkit-test-runner [ experimental:CSSPaintingAPIEnabled=true ] -->

<canvas id="paint" style="width: 150px; height: 150px;" ></canvas>

<script id="code">
const canvas = document.getElementById('paint');
canvas.width = 150 * window.devicePixelRatio;
canvas.height = 150 * window.devicePixelRatio;

const ctx = canvas.getContext('2d');
ctx.scale(window.devicePixelRatio, window.devicePixelRatio);

for (var i = 0; i < 6; i++){
  for (var j = 0; j < 6; j++){
    ctx.fillStyle = 'rgb(' + Math.floor(255 - 42.5 * i) + ',' +
                     Math.floor(255 - 42.5 * j) + ',0)';
    ctx.fillRect(j * 25, i * 25, 25, 25);
  }
}
</script>