Yeah, I filed https://github.com/google/boardgame.io/issues/9 https://github.com/google/boardgame.io/issues/9. The source in github does check if the cell is f

Yeah, I filed https://github.com/google/boardgame.io/issues/9 https://github.com/google/boardgame.io/issues/9. The source in github does check if the cell is filled [1] but the demo code must be from an earlier version that didn't. [1] https://github.com/google/boardgame.io/blob/master/examples/tic-tac-toe/tic-tac-toe.js#L81 https://github.com/google/boardgame.io/blob/master/examples/...