Sample Tic Tac Toe app written in Swift Core algorithm is in TTTEngine. It implements a MiniMax algorithm to recursively iterate through all possible moves. It will seek winning moves while avoiding losing moves. The result is unbeatable, but not optimal. Board maintains the TicTacToe board, including determining if someone has won, if its a draw and if moves are valid. It interprets touches and forwards them to its delegate. TTTBoardView is a custom view which uses Core Graphics to draw the board and pieces. ViewController programmatically creates the app's view and manages game play. Move evaluation is done on a background thread and the result posted back on the main thread via GCD. Placehold is present for an Apple Watch extension but not implemented. This project is built with and requires Swift 3.0 as part of Xcode 8 beta.