Firstly, I used an object oriented approach to code a connect four game that allows player input through the command line and represents the board with printed symbols.
Then, I used the idea of "ply" to create a digital player that for each turn, considers each position it could play in and only calculates whether it will win with this move.
Then, using recursion, I made this digital player think several moves ahead. Even just a few ply is enough to beat me and all my friends!
My entire class of 60+ people tested our connect four AIs against each other, and my AI did the best out of all!