caption: The image shows a drawing of a sea urchin on a piece of paper. The paper is filled with various types of shells, each with its own unique shape and texture. The shells are arranged in a circular pattern, with some overlapping each other. The colors of the shells range from light brown to dark brown, and some have a glossy sheen. The background of the paper is a light cream color, and the text on the paper reads "Sea urchins".