Swiftris is a tutorial on building iOS applications by walking the user through the development of a clone of the renowned puzzle game known as Tetris. The Swiftris site can be found on their website.

It should be noted that the guide is for Swift 2 and as such does not convert seemlessly to Swift 3. It isn't hard to convert between the two, but there are a few differences. A lot of the differences are function renames to use the parameter pass in arguments, and some just remove part of the name of the function.

Another notable difference (I haven't fully looked into it yet, and I have not developed enough with Swift 2 to be certain) is that in Swift 3 the argument name of the first element is necessary when passing in elements to a function, while in Swift 2, this did not seem to be the case.