Mencius said: “Even with Li Lou’s sharp eyes and Gongshu Ban’s (Lu Ban’s) superb craftsmanship, without compass and square, one cannot draw perfect circles or squares. Even with Shi Kuang’s acute hearing, without the six pitch standards, one cannot tune the five notes correctly.”
When the crown prince of Teng (later Duke Wen of Teng) was traveling to Chu, he passed through Song and went to see Mencius.