Looks really nice. A few things that I think might make the presentation a bit clearer:<p>1. Using polar coordinates makes the maths a lot cleaner than using Cartesian coordinates. However you then either need to explain polar coordinates, or you assume people remember polar coordinates from high school which is often not the case in my experience.<p>2. I think the positioning of the points is a little bit opaque. I was expecting to see (r * cos theta, r * sin theta) and it took me by surprise to see an addition in there. Either just noting that stupid computer graphics libraries don't put the origin at the center, or adding that translation later (which is a chance to talk about function composition) might be beneficial.<p>(I've written my own take on this same topic, starting at <a href="http://www.creativescala.org/creative-scala/polygons/" rel="nofollow noreferrer">http://www.creativescala.org/creative-scala/polygons/</a> It will take a little bit more than 5 minutes to get through it :-) It's really fun and you can do a huge amount with parametric curves.)