What's the difference between a 1-pt and a 2-pt perspective?

Here is another of my favorite spreads from the new book... I love these diagrams, as I can see the ah-ha moments when people in my workshops FINALLY understand what makes a view a one-point perspective versus a two-point perspective.  It's not rocket science!  It is so easy once you know what to look for.  

Swedish Nina Johansson's glowing one point/elevation view of a small building, paired with Murray Dewhurst from New Zealand and his sketch of another small building...one is 1-pt and the other is 2-pt...depends on where the sketcher is standing!!!

Much more in the new book, Understanding Perspective.