I downloaded the SW World 2017 presentation "Curve and Surface Modeling" by Mark Biasotti and in it there are points where you can press a button to open an example relating to the point he is making. When I click on them I get an error "Could not open file" I assume it is because they did not down load with the PDF. I emailed Mark and he has graciously offered to upload them here. I have attached the presentation and I'll wait for Mark's reply. Thank You.