Q: In Chinese, guiju refers to rules. In fact, these two characters, gui and ju, referred to two tools in ancient times. Do you know what they were? 

汉语中的“规矩”是啥意思大家伙都知道吧~其实，“规”和“矩”这两个字分别指代古代的两种工具。究竟是什么呢？一起来看看吧~

A: Gui was the tool used to draw circles, like today’s compasses (圆规). Ju was used to draw squares (方形), like the try square (曲尺) today. 

Gui and ju were useful tools. They helped ancient people draw patterns (图案). Geometry (几何学) got better thanks to them. Ju appeared in records about what is known as the Pythagorean Theorem (勾股定理). This theorem was one of the most important findings in Chinese math history. 

规和矩是十分有用的工具，可以帮助古人作图，几何学的进步也得益于它们。因为勾股定理，“矩”被熟知——这个定理是中国数学史上最重要的发现之一。

Ancient Chinese people created the tools very early. The Records of the Historian (《史记》) said that Dayu, the man who fought the flood (洪水), used gui and ju.

中国古人很早就创造了“规”和“矩”。《史记》中记载道，大禹治水，用的便是规和矩。

In the brick carving patterns (砖雕图案) of the Han Dynasty (206 BC-AD 220), there are such pictures: the mythological figures (神话人物) Fuxi holds a ju, while Nyuwa holds a gui. 

在汉代(公元前206年-公元220年)的砖雕图案中，有这样的画面:神话人物伏羲手持矩，女娲手持规。

Ancient people compared (比作) guiju to laws and rules. Later, they used the phrase to refer to rules. 

古人把规矩比作法律和规则。后来，他们用这个短语来指代规则。