$(document).ready(function() {
  var heroes = $('.hero'),
      hero = heroes.first(),
      height = hero.height();
  heroes.not(':first').css('top', -height);

  var interval,
      time = 6000;

  function advance() {
    clearInterval(interval);
    var a = hero.attr('id').substr(5);
    hero.animate({'top': -height}, 300, function() {
      var b;
      if (!hero.next().length) {
        b = heroes.first();
      } else {
        b = hero.next();
      }
      b.animate({'top': 0}, 300);
      hero = b;
    });
  }

  setInterval(function() {
    advance();
  }, time);
});