The residence of the living is called "Yang Zhai", and the grave is the residence of the dead, called "Yin Zhai". According to the funeral custom of Yixing, when snakes are found around the coffin, it is considered that the coffin is a good place and a "busy place", and the coffin is not suitable for burial elsewhere. If a snake is found in the pit when moving the ancestral grave, it is considered that future generations can develop. It's better to look at the tortoise and say it's "imperial court" It is unlucky to see eels, because "eels are begging sticks", and future generations will fall.