Tutorial for the image viewer can be found here: https://www.hackingwithswift.com/read/1/overview
Tutorial for the Dragging Views tutorial can be found here: https://www.ioscreator.com/tutorials/dragging-views-gestures-tutorial-ios10
Tutorial for the Tetris Ripoff can be found here: https://www.bloc.io/tutorials/swiftris-build-your-first-ios-game-with-swift#!/chapters/678