unit 4 lesson 1, assignments 1 & 2
unit 4 lesson 1, assignment 3
unit 4, lesson 1 assignment 4: done the suboptimal way, inside app delegate #didFinishLaunchingWithOptions:
unit 4, lesson 1, assignment 4: right way, inside contained view's #initWithStyle: ctor
unit 4, lesson 1, assignment 5