var cPic = 0;
var maxPic = 28;
var changeTime = 8000;

function show(tDiv, vDiv){
	var myFx1 = new Fx.Tween($(tDiv), {duration: 'long'});
	var myFx2 = new Fx.Tween($(vDiv), {duration: 'long'});
	myFx1.start('opacity', '1', '0');
	myFx2.start('opacity', '0', '1');
}

function changePic() {
	var nPic = Math.floor(Math.random()*maxPic) + 1;
	while(nPic == cPic)
		nPic = Math.floor(Math.random()*maxPic) + 1;
	show('p' + cPic, 'p' + nPic);
	cPic = nPic;
	setTimeout('changePic()', changeTime);
}