An underwater mystery that once puzzled experts was the discovery of strange drawings in the sand with found on the seabed off Japan. After a decade they found their origin & why they suddenly appeared and disappeared until they finally managed to discover it. The author of these amazing formations, almost 2 meters wide, was a newly discovered species of puffer fish measuring no more than 12 centimeters. Subsequent studies determined that they were ornate circles to attract mating partners #fish