The rule says that for every 20 minutes spent looking at a screen, a person should look at something 20 feet away for 20 seconds.
Download and open with Script Editor
- Fill your Mac password into the placeholder
- File -> Export..
- File Format Choose Application, check Stay open after run handler & Run-only
- Delete the script file
- Run Application Add App into Mac Starup
- System Preferences -> User&Groups -> Login Items
- Add App into the list