window.addEvent('domready', function() {
  elDisplay= $('display');
  elBoxContainer= $('hidden');
  fx = new Fx.Tween(elDisplay,{property:'opacity', duration: 600 });
  var timer;

  var runChain = function() { 
    elBoxOld = elDisplay.getElementById('box');
    //aBoxes = $$('div#hidden div#box');
    aBox = elBoxContainer.getChildren()[0];
    //if (aBoxes.length > 1) {
    if (aBox != null) {
      //First box will be the one currently displayed, so we want the next
      //elBoxNew = aBoxes[1];
      fx.start(1,0).chain(
        function(){
          aBox.inject(elDisplay);
          elBoxOld.inject(elBoxContainer);
          this.start(0,1);
        }
      );
    } else {
      runChain = $clear(timer);
    }
  }

  timer = runChain.periodical(10000);

});