It could be that a random distribution-- I don't have colored chalk here I don't think, so I will use a dash line to represent the fat-tailed distribution.

这是一个随机分布,这里没有彩色粉笔,我就用虚线,来表示长尾分布

耶鲁公开课 - 金融市场课程节选

Let me draw a quick picture in chalk here.

我用粉笔画一个简单的图。

哈佛公开课 - 计算机科学课程节选