function start()
{
  clock = 1;
}

function update()
{
  clearScreenWithColor(black);

  width       = 100 + (Math.sin(clock/300*2*3.14) * 50);
  redAmount   = Math.floor(150 + (Math.sin(clock/300*2*3.14) * 100));
  greenAmount = Math.floor(150 + (Math.cos(clock/300*2*3.14) * 100));
  blueAmount  = Math.floor(150 + (Math.sin(clock/300*2*3.14) * 100));
  circle(200, 200, width, "rgb(" + redAmount + "," + greenAmount + "," + blueAmount + ")");

  clock++;
}