The Octagon Theory is an iOS abstract strategy board game like chess, othello, checkers. While The Octagon Theory can be played by two humans via pass-n-play it is mainly designed for one human to play against the AI. It is a universal version for iPhone, iPod Touch, and iPad.
TOT TableTop is an iPad-only version of The Octagon Theory that is mainly designed to be place on a table to be played by two humans. But a human player can play against the AI if another human player isn't available.