4 So this is 16 times 4 equals 64 and though this is not proof by any means, it's not a formal proof because here is one example that happens to prove my point.

所以是16*4，即,尽管如此，这并不是严格的证明,因为是这个例子碰巧证明了我的观点。

哈佛公开课 - 计算机科学课程节选