Tell me what kinds of natural compasses are written in the text.

The text describes four natural compasses: the sun, the North Star, the leaves of large branches and the snow in the ditch. The text of Lesson 17 "If You Lost Your Way in the Wild" in the second volume of the second grade Chinese language in the unified edition reads: "At noon, the sun is in the south, and the shadow of the big tree points to the north. On a clear night, the direction of the North Star is North. At night, the North Star can point us to the north. On cloudy and rainy days, the side with thicker leaves is to the south, and the side with thinner leaves is to the north. After it snows, the side of the snow in the ditch melts faster, and the side that melts slowly is north. One side is the south. "This passage describes that when you are lost in the wild, you can determine the direction according to the sun, the shadow of the big tree, the North Star, the leaves of the big branches and the snow in the ditch, so as to find the correct direction. The principles of these natural compasses are based on the laws of natural phenomena, such as the rising and setting of the sun, the growth direction of large branches and leaves, the constant position of the North Star, etc. By observing and judging these natural phenomena, we can help us determine the direction and avoid getting lost and taking the wrong path.