After having explored how to build normal apps with the last two apps, let's go back to games.

These apps will use two useful frameworks that iOS provides for casual game developers—SKSprite and SKScene. The former is a handy and powerful 2D game framework that provides a physics engine based on Box2D. The latter allows indie game developers to implement three-dimensional games.

Let's start using the first framework by implementing a nice clone of Flappy Bird.