The Three Fences
This video presents the same text shown beside it, spoken and on screen. It adds nothing the text does not say.
State
The classical game machinery assumes three fences: exactly two players, perfect information — both see the whole position — and zero-sum, exactly opposed interests.
Show
Chess and checkers live inside all three; poker's hidden cards step outside the second at once.
Watch for
Each fence is a declared scope, not a law of games — lifting them opens real fields.