What does it mean that the gate of the Forbidden City is paved?

Explanation: The base with knocker on the old door is made of copper and shaped like a beast.

From: a copper plate attached to the door to make a ring. Hanshu. Volume XI. Mourning the Emperor: "The bronze tortoise and snake shop in front of Xiao Yuan Temple rang for the first time." Selected works. Yi Fu. Wu Fu: "The account is full of enthusiasm, standing in groups, and the first bean shop is brilliant. 」

The shop head is the door decoration of traditional Han architecture, which has the significance of exorcism. Most of the ornaments on the door are in the shape of animal heads. Take gold as it, and call it a gold shop; Call it a silver shop with silver; Take copper as it, and call it a copper shop. Its shape, there are smelting elephant, smelting animal kiss, smelting elephant, covering its goodness and keeping its economy. Others smell turtles, snakes and tigers to ward off evil spirits. The melting of the inscription ring of the animal head has long existed on bronze ornaments in Shang and Zhou Dynasties.