《史记·七十列传·龟策列传》
当行，首足开。不宜行，足肣首仰，横吉安，安即不宜出行。
行，首足开；不行，足肣首仰，若横吉安，安不行。
Appropriate to go out, the head and feet are open. Not appropriate to go out, the feet are bent and the head looks up, while the cross is auspicious, auspicious means it is not appropriate to go out.