This little program helps in preventing eyestrain by reminding you to look at an object 20 feet away for 20 seconds, after every 20 minutes (according to 20-20-20 rule), if your work involves looking at computer screen for long hours.

This program runs in the background and after every 20 minutes an overlay will be displayed in front of your currently running applications with a countdown timer and it will hide itself after 20 seconds.

Source : Discovericl blog, 20-20-20 rule

You can download it for windows OS from here.

See Licence File here.
Feel free to make PR & make it better.