《淮南子·说林训》
没有规矩不能成方圆，没有准绳不能定曲直；使用规矩准绳的人，也必定有使用规矩准绳的法则。
非规矩不能定方圆，非准绳不能正曲直，用规矩准绳者，亦有规矩准绳焉。
Without a compass and a square, a circle or a rectangle cannot be made; without a measuring line, a straight or curved line cannot be produced; and the person using the compass, the square, and the measuring line must certainly have his own rules for using these tools properly.