The maple seed is a natural wonder. It is the perfect flying wing grown on a tree. It's like saying that there is a tree that produces watches. The seed is made up of a bunch of veins. At the bottom, where the actual seed is located, the veins are closely packed together. Further up, they spread out. They do this in such a well organised manner that an aerodynamic wing is formed. At the left side, the wing is a bit thicker and heavier. At the right side it is thin and lightweight. The reason why it flies in circles is probably that the seed is at one side of the wing and not in the center. We could do a test. Cut out the seed and mount it in the middle. Will it fly straight?