AnonymousTransition.js

['pushTest2', function(previous, next, duration, instance){
	var distance = instance.element.getStyle('width').toInt();
	next.setStyle('left', distance);
	new Fx.Elements.start({
		0: { left: [-distance] },
		1: { left: [0] }
	});
	return this;
}],

Stored.js

Fx.Elements.implement({
	setElements: function(elements){
		this.elements = this.subject = $$(elements);
		return this;
	}
});

SlideShow.helpers = {

	fxElements: new Fx.Elements,	

};

['pushTest2', function(previous, next, duration, instance){
	var distance = instance.element.getStyle('width').toInt();
	next.setStyle('left', distance);
	SlideShow.helpers.fxElements.setElements([previous, next]);
	SlideShow.helpers.fxElements.start({
		0: { left: [-distance] },
		1: { left: [0] }
	});
	return this;
}],