curTime - lastAnimateTime;
      lastAnimateTime = curTime;
      //console.log("Time is now "+animationTime);
    }
    update_time();
    document.getElementById('slider').value = progress();
    requestAnimationFrame( animate  );
  }
</script>

<style>
 .button { 
  display:flex;
  width:50px;
  height:50px;
  margin:10px;
  border:2px solid #000000;
  box-shadow: 3px 3px 5px #888888;
 }
 .button:hover { 
  cursor:pointer;
  background-color:#CCF;
 }
 .slider{
  flex-grow:1;
  width:auto;
  height:40px;
