This article is devoid of interesting content. The central thesis is: "In order to understand something, you need to develop insight. Well, duh. It does not explain how to develop 'insight', it does not explain what constitutes 'insight' and it does not even justify that the main example, visual representation of a derivative, results in 'insight' and results in people having an easier time grasping and using derivatives. As I am skeptical the example actually grants that 'insight' (it may seem obvious to you and me, but that is the trap we must avoid. The point is that it isn't obvious to many), this article did not add anything to my understanding of 'teaching' or 'understanding' at all.