Bouncy Balls
A simple animation. Lots of colored balls bouncing along.
HTML5 version (2019)
Pure CSS animation. No JavaScript involved! Works fine on Google Chrome, Firefox, Opera. Will be laggy on web browsers without hardware acceleration.
You can see it in action here:
https://helderman.github.io/bouncy-balls/html5/balls.html
Scratch version (2018)
You can see it in action here: