DigestSwiftUI is an iOS 15 SwiftUI app that requires Xcode 13. It uses the new TimelineView to continuously display a view of images. It also uses the GeometryReader to layout several other views. I haven't installed the iOS 15 beta on my phone so this has only been tested in simulators.
DigestSwiftUI is licensed under the Unlicense. See the LICENSE file for more information, but basically this is sample code and you can do whatever you want with it.