If you search Google for [metronome] on your desktop or mobile device, you will see an interactive metronome. A metronome is a device used by musicians that marks time at a selected rate by giving a regular tick.

The Google metronome ranges from 40 to 208 beats per minute.

Here is a video of it in action:

Here is a static photo:

This was actually spotted a couple weeks ago by Google OS.

Forum discussion at Twitter.