I have stumbled upon some interesting exercise whilst reading the "Category Theory for Scientists" book.
Below is the universal property of fiber products:
By using the universal property, I can try placing some set A, connect it to the X, X', Y, Y' through some functions and thus have two unique arrows spawning from it to the W and W'. However, nothing that could be used to create a direct connection between the W and W' comes out from that.
Any suggestions how this could be solved?