Project 2 - XOR gates

Just to make it clear about the submission instructions in section (6): “You may not use XOR gates.”
Can we use auxiliary circuit which will include xor implementation using only AND, OR and NOT gates?

Thanks!

You may use your own implementation of XOR if really necessary. However, you should design a circuit based on the background/mathematical formulation given in the assignment. Don’t use a formulation which doesn’t follow the recursive formulation given.

As a follow up on that question, could I add my own implementation of XOR gate as a another circuit.

Yes, if you want to use your implementation of XOR, it’s a good idea to make a different circuit for it.
Modular designs are always nice.