Develop a basic game using design patterns to enhance the usability of a game

I was tasked with creating a system that takes advantage of design patterns in order to improve the usability of the system (does not have to be a game). Additionally, we also have to create the system twice using two different design patterns.

I decided to create a game of tic tac toe. The first design pattern that will be implemented is the command design pattern, which will give the player the ability to undo his/her move.

The issue is I cant think of how a second design pattern would help improve the usability of a game of tic tac toe. What design pattern would be best suited towards the problem. (keeping in mind that it has to in some way improve directly the usability of the system).

I think the task is a bit weird. My understanding of design pattern is that you should not aim towards it, rather use it to improve the overall quality of your code. That being said, the question states that I have to put it as a primary goal.