Scrollbound animations with amp-position-observer and amp-animation

The following animation does one round (12pm-6pm) via scrolling when fully visible between the middle 80% of the viewport

Custom visibility start-end with amp-position-observer and amp-animation

The following animation will start when the scene is 50% visible and pauses when 50% invisible

Custom visibility end with amp-position-observer and amp-video

If played, the following video will pause when 20% invisible