《论衡·卷十七·是应篇》
假使蓂荚生在殿堂上，君王坐在门窗之间，观察蓂荚的生长情况以此知道日子的多少，这才差不多可以说是有益的了。
使荚生於堂上，人君坐户牖间，望察荚生以知日数，匪谓善矣。
If the green pods were born in the hall, the emperor would sit between the doors and windows, observe the growth of the green jade pods and know the number of days. That's about it.