window.onload = function() {
  var canvas = document.getElementById("canvas"),
      context = canvas.getContext("2d"),
      width = canvas.width = window.innerWidth,
      height = canvas.height = window.innerHeight;
  
  context.translate(0, height/2);
  context.scale(1, -1);
  
  for (var angle = 0; angle < Math.PI * 2; angle += .1) {
    
    var x = angle * 100,
        y = Math.sin(angle) * 200;

    context.fillRect(x, y, 5, 5);
  }
 
}