This is After Effects tutorial video How to make clock animation run in real time with After Effects. Used: Slider Control, ...

The end product is an animated LED clock that is capable of displaying the time in numerical format, as an analog clock face, and with plenty of animations thrown in to mix things up.

Google Clock has been updated to version 7.0 and it brings a full Material You redesign along with it, including a slick new animation, too.