What is an example of XOR? I have a doubt regarding the below lines in "deep learning" book.
I don't have a very good math background, I grasp most of the concepts with examples. First they describe this:

Which I understand it as ie $x_1=$ house_size ,    $x_2=$year_built and $f(x,w)$ shall be the house price.
But I can't think of an example for the below:

I see in wikipedia that XOR is exclusive 'or', so I understand that it means strictly either 'a' or 'b'. But what is an example of this?

Below, an electric circuit modelling the X-OR operator 

