Hey,   When animating an unknown number of elements like so: var timeline = new TimelineMax({repeat:-1}), items = document.querySelectorAll('.item'), startDuration = 20; for(var i = 0; i < items.length; i++) {   var myDelay = (i * 0.5);     animate(items[i], myDelay);   } function animate(item, delay) {   var a = TweenMax.to(item, startDuration, { rotationZ:'360', ease:Linear.easeNone, repeat:-1 });   timeline.add(a, delay); }   What is the best way to modify the duration/speed of an