How many kinds of caves are there in the geomantic omen of Yin House?

There are four main forms: nest, pliers, chest and convex, and there are also strange points in the position, such as riding a dragon, cutting off the customs and riding a dragon upside down. I don't think it is necessary to blindly pursue form and position, because everything in a real cave is natural, as long as it conforms to the surrounding geographical environment, it is enough to collect mountains, eliminate evil and absorb water.