https://developer.apple.com/library/archive/referencelibrary/GettingStarted/DevelopiOSAppsSwift/ImplementNavigation.html https://www.raywenderlich.com/5895-uikit-drawing-tutorial-how-to-make-a-simple-drawing-app
https://developer.apple.com/documentation/uikit/pencil_interactions/handling_input_from_apple_pencil https://developer.apple.com/documentation/uikit/touches_presses_and_gestures/handling_touches_in_your_view https://developer.apple.com/documentation/uikit/touches_presses_and_gestures/leveraging_touch_input_for_drawing_apps