Retrieving some items from my students, that might disappear when deleting their blogs from the experience of educational innovation, I've seen this group Protagoras linking pi polygons and playfulness in a very successful.

The educational approach in the form of competition is a valuable resource that does not have to lose the rigorous training approaches. On the contrary, knowledge to explore critically and entertaining couple. This group of students has been successful in its approach, already quoted at the time.