I made this little thing for myself months back to help from getting headaches and sore eyes after working on a screen all day. It's really simple and just reminds you to take a 20 second break from looking at the screen, every 20 minutes. Just hit play and leave it running in the background.
Anyway- thought I'd stop being selfish with it and share it publicly now i've cleaned it up a little. Hopefully some of you find it useful!