Your question is Design Tic Tac Toe. Take a moment with it on the right.
Talk me through your thinking if you like. When you're confident, submit your answer and I'll grade it like a real screen (7/10 or better passes).
Design a game like tic tac toe.
Clarify the game rules, API and client/server responsibilities, state management, move validation, and how you would support a computer opponent. Discuss how the design would change if the game became a heavily used online service. If you introduce machine learning for move selection, explain the model, training data, serving path, evaluation, and fallback behavior.