You'll start your four hour cycle with a cool blue wallpaper, and then every 30 minutes the wallpaper will change color to indicate that time is passing and you may want to take a break.

There are 40 wallpapers in total that you can find at their Telegram posts here. And as a bit of a bonus leak, they also shared the colors for the upcoming Pixel 10 series, sans Pixel 10 Pro Fold ...