YAHOO.util.Event.onDOMReady(function (ev) { 
	/* Assign 3 shells to the visible container. */
	document.shells = YAHOO.util.Dom.getChildren('visible_shell_container');
	document.shells[0].style.left = '0px';
	document.shells[0].id = 'shell0';
	$(document.shells[0].id).show();

	document.shells[1].style.left = '282px';
	document.shells[1].id = 'shell1';
	$(document.shells[1].id).show();
	
	document.shells[2].style.left = '562px';
	document.shells[2].id = 'shell2';
	$(document.shells[2].id).show();
	
	
	setTimeout("replaceShell(0); setInterval('replaceShell(0)', 12000)", 4000);
	setTimeout("replaceShell(2); setInterval('replaceShell(2)', 12000)", 8000);
	setTimeout("replaceShell(1); setInterval('replaceShell(1)', 12000)", 12000);
});

function getInvisibleShell() {
	var chosen_shell = null;
	
	do { 
		var random_index = Math.floor(Math.random() * (document.shells.length));	
		chosen_shell = document.shells[random_index];	
	} while (chosen_shell.style.display != 'none');
	
	return chosen_shell;
}

function replaceShell(index) {
	var new_shell = getInvisibleShell();
	
	var left_val = '0px';
	if (index == 1)
		left_val = '282px';
	else if (index == 2)
		left_val = '562px';
	
	var shell = YAHOO.util.Dom.get('shell' + index);
	shell.id = '';
	Effect.Fade(shell, {duration: 2.0});

	new_shell.id = 'shell' + index;
	new_shell.style.left = left_val;
	Effect.Appear(new_shell, {duration: 2.0});
}