Today, from my Mediterranean classmates (from Greece, Italy and Albania), I found out that a creature called “Sea Urchin” exists and this is what Wikipedia has to say about it: “Urchins typically range in size from 6 to 12 cm (2.4 to 4.7 in), although the largest species can reach up to 36 cm (14 in). Sea urchins earlier have bilateral symmetry, but they develop five-fold symmetry as they mature. So their bodies consist of five equally sized parts radiating out from their central axes.
Sea urchins are sensitive to touch, light, and chemicals. Although they do not have eyes or eye spots, the entire body of most regular sea urchins might function as a compound eye.”