function Observer(bgs) {

	var arr = $w(bgs);
	$('observer').hide().update('<img src='+arr[1]+'><img src='+arr[2]+'>');
	Bg(arr[0]);

	new PeriodicalExecuter(function(pe) {
		// document.getElementsByTagName('body')[0]
		$('start').setStyle({
			backgroundImage: 'url('+arr[0]+')',
			backgroundRepeat: 'no-repeat',
			backgroundAttachment: 'fixed',
			backgroundPosition: 'center top'
		});
		arr.push(arr[0]); arr.shift();
		$('observer').hide().update('<img src='+arr[1]+'>');
		Bg(arr[0]);
	}, 8);
}

function Bg(bg) {
	$('observer').setStyle({
		width: document.viewport.getWidth()+'px',
		height: document.viewport.getHeight()+'px',
		backgroundImage: 'url('+bg+')',
		backgroundRepeat: 'no-repeat',
		backgroundAttachment: 'fixed',
		backgroundPosition: 'center top'
	}).appear({ duration: 0.5 });
}