Game design for iOS with Swift and Core Graphics. Sample Tetris application.

Hi, today I decided to talk a little about my experiments with iOS development, and specifically game development with a relatively new but already very popular language Swift, which recently revealed it's sources.

Sources are here:
https://github.com/grimcoder/tetriz
and the game is published here:
https://itunes.apple.com/kn/app/falling-figures/id1048856850?mt=8