Outline is a very important aspect of surfboard design. A good outline is curvy in the areas where pressure is applied (towards the tail) and straighter in areas that are built for speed (the center of the board). Curves make you turn, straight allows you to go fast. Curves are also more forgiving, and this is why a surfboard is curvy in the nose. Bumps or wings are sometimes thrown in towards the tail of the board, providing a pivot point. This will loosen up a board by pulling in the tail for easier rail-to-rail transitions. A wider board is naturally faster through more planing area, while a narrower board will go rail to rail faster, but sink easier. A good board has natural speed, or can generate it easily.