《淮南子·说林训》
现在有六尺宽的席子，平铺在地上，一般性的人越过它并不困难；但如果将席子竖立起来，就是弹跳力出众的人要跨越它也不是件容易的事：这是因为席子摆放的态势不一样。百颗梅子足以调配一百人食用的酸汁，而一颗梅子就不足以调配一个人所需的食用酸汁。
今有六尺之席，卧而越之，下材弗难；植而逾之，上材弗易；势施异也。百梅足以为百人酸，一梅不足以为一人和。
There is now a six-foot wide mat laid out on the ground, an ordinary person can step over it without difficulty; but if the mat is set upright, it would be hard for even someone with great leaping power to jump over it: this is because the ways in which the mat is placed are different. One hundred plums are enough to prepare sour juice for one hundred people, but one plum is not enough to prepare sour juice for one person.