#!mojo mojo:sky_viewer
<sky>
<style>
square {
  margin: 50px;
  height: 100px;
  width: 100px;
  background-color: green;
}
</style>
<square></square>
<script>
var square = document.querySelector('square');
var timeBase = 0;

function animate(time) {
  if (!timeBase)
    timeBase = time;
  var delta = time - timeBase;
  var rotation = Math.floor(delta / 10);
  square.style.transform = 'rotate(' + rotation + 'deg)';
  requestAnimationFrame(animate);
}

requestAnimationFrame(animate);
</script>
</sky>