caption: The image shows a black and white drawing of a set of four different types of coils, each with a unique shape and texture. The coils are arranged in a symmetrical pattern, with the largest coil in the center and the two smaller coils on either side. The colors of the coils range from light to dark, with some having a glossy finish and others having a matte finish. The background of the image is a plain white, allowing the coils to stand out.