I totally disagree. Saying that "pi isn't really about circles" is totally wrong and removes it from any properties people can easily grasp. He argues that pi

I totally disagree. Saying that "pi isn't really about circles" is totally wrong and removes it from any properties people can easily grasp. He argues that pi should be defined as a property of a differential equation. This is obviously stupid, because it makes mathematics impossible to teach. For me it gets the worst when he claims that Euler's equation has no relation to circles. Which is, really, really stupid. The complex exponential represents rotations in space. This connectiom can only arise when you understand first that pi is in fact about circles. The circle is the underlying principle of pi.