How does recursion work its way back?

Question

I\'m working to understand recursion more in depth and I\'m struggling with WHY it works the way it does. I know that this function returns the square of the previous return

Answer 1

You're thinking about the steps linearly, while the execution is actually nested (represented by indenting):

call p1a(3)
    call p1a(2)
        call p1a(1)
            return 2
        return pow(2, 2)
    return pow(4, 2)

So the final return returns the value 16.