I made an iOS app to use the front of my phone as a low-intensity flashlight.
I can choose the color of the screen and adjust the brightness.
This sort of thing is useful if you have a migraine, or don’t want to lose your night vision, or don’t want to wake someone else up. It’s a Storyboard app. I might re-make it again to learn how to do the layout just in code, and also make it again with SwiftUI.