I just stumbled on a superb HTML5 animation today, gracing a lead generation minisite for InVision Studio.
InVision is a UI (user interface) design tool currently in development, looking very similar to the Adobe effort I am currently using (Adobe XD). Its all about interactions and reactions, element animations and layouts, fluidity and responsiveness. So it makes sense that their marketing site showcases these concepts using the same features.
I was well impressed with the ingenuity their designers have shown in creating their epic 'scroll journey'. This site goes well beyond the usual 'things float in from the side' interaction as you scroll down the page. Elements twist and flow seamlessly as you travel down, sometimes becoming parts of larger elements which then act as if they are the canvas (a scroll within a scroll)... and so on...
Well done - a call to arms for web animators!