window.onload = function(){
  var inside = $('inside');
  inside.x = 0;
  inside.y = 0;
  inside.drawBackground = function(){
    $('inside').setStyle('background-position', inside.x + "px " + inside.y + "px");
    inside.x = inside.x - 8;
  }
  setInterval(inside.drawBackground,30);
  document.body.addEvent('mousemove',function(e){
      inside.y = e.clientY; 
			inside.x = e.clientX;
  });
}