One number drives the whole shape, and it runs from 0 to 1: how far the coil has opened. Any value gives a real frond, which is why it can be dragged to, played backwards, or animated smoothly — nothing here is drawn by hand and there are no frames. The knobs below change the kind of frond it is. None of them draws anything; they set how the curve bends and where the leaflets sit, and the shape is what follows. See a whole year of a tree →