The first Android app in the Google Play Store implementing an optimal AI for the game of Quantum Tic-Tac-Toe. Features: • Single Player mode. • Varying levels of difficulty. • Multiplayer mode (on the same device). • Undo moves. • Optimal AI ("X" always wins)! Game rules: https://en.wikipedia.org/wiki/Quantum_tic-tac-toe#Gameplay This app was developed as part of my MEng thesis in the Department of Electrical and Computer Engineering of the University of Patras.