When Randall Munroe’s XKCD published this clock, I decided I just had to have it on my desktop. I took the images and wrapped them in a bit of script to keep the rotation of the center up to date. It also adds the ability to select a time zone to see the actual time there.
Here’s a direct link to the page, so you can do with it as you see fit. I originally had it running in a MacOS widget, but those are long dead at this point.