As I understand it this could be a bit tricky or messy.   The key to getting the scrollY of the window to effect the movement of the box is to use ThrowPropsPlugin.track() method to track the velocity of the scrolling. When the user is done scrolling you can create a tween of the box based on the velocity of the scrolling.   Definitely study the ThrowPropsPlugin docs: https://greensock.com/docs/Plugins/ThrowPropsPlugin  and the track() method: https://greensock.com/