I've been doing some reading. It looks like Babbage only had the idea of building a tic tac toe machine to raise money: 'I imagined that the machine might consist of the figures of two children playing against each other, accompanied by a lamb and a cock. That the child who won the game might clap his hands whilst the cock was crowing, after which, that the child who was beaten might cry and wring his hands whilst the lamb began bleating'. [http://www.hrc.wmin.ac.uk/theory-babbagesdancer3. html] Then he never built it, because the victorians lost interest in automata and he thought he would not make money with it. The image in the link is a trial part (small piece) of the analytical engine. The machine was (would have been) much more capable than just being able to play a game of tic tac tac toe. Tic tac toe is easily programmable, even with simple elements like relays or just mechanical switches and lights if you force a player into particular moves. The all purpose analytical engine (not to confuse with the difference engine, which is a machine for tabulating polynomial functions) would be realy impressive. For example the way Babbage used his "anticipatory carriage" which could add all carries at once. This is something electronic circuits can't do. It was never built. His son put something together that looks a bit like the mill, but was never intended to run together with program or memory.