1. The problem statement, all variables and given/known data Draw out the game tree for tic-tac-toe 2. Relevant equations 3. The attempt at a solution I'm just thinking about it and I don't know how to start. To draw out the entire gametree, we'd have thousands and thousands of branches. So based on symmetry there is only 3 starting points we need to reference I think. From there I'm just trying to see which plays would be symmetric, but I'm still lost The key is to use symmetry somehow to make the game tree more reasonable, but I'm really struggling and just looking for advice/hints.