In china they are put together to represent a contradiction.

在中国，剑和盾被放在一起代表着矛盾。

Long,long ago a man was selling his spear and shield.

很久很久以前，有个人在卖他的矛和盾。

He said that his spear was the sharpest one and could cut through any shield.

他说他的矛是最锋利的，可以刺穿任何盾牌。

And then he said his shield was the toughest one and nothing could cut through it.

然后他说他的盾是最坚硬的，没有什么能穿透它。

But what would happen if the spear was used to stab the shield?

但是如果用矛来刺盾会发生什么呢?

The man couldn’t answer the question.

这个人无法回答这个问题。

The story tells us not to be caught in maodun.

故事告诉我们不要陷入矛盾。

Maodun describes the relationship between things on the opposite positions.

矛盾，描述的是事物在相对位置上的关系。