Thanks to our Subbable subscriber SlugBooks.com - head over to http://www.slugbooks.com to find cheaper textbooks for college or university. And go to http://www.subbable.com/minutephysics if you want to support MinutePhysics on Subbable! And also to our Subbable subscriber Mathias Larssen! Paper on diffraction through the lens of the human eye: http://goo.gl/XEdMVd "Shape of stars and opt