If you moved this same top-left petal from top to bottom

You can see how this would be the case in the image below, which shows a rose vibrator with all its petals closed. You will notice that when you rotate each of these petals individually, they move in different directions at different speeds. For example, if you rotated the top-left petal from left to right (as shown) it would open up and then close again as it approached vertical. If you moved this same top-left petal from top to bottom (straight down), however, it would not change direction at all since there is nothing for it to rotate around here; instead, it would simply remain open until gravity pulled down on its weight and pushed it closed again.