I started using wood picks and found them to give a better sound (no 'clicking') and easier to hold. So I started making my own from different types of wood. Each wood sounded slightly different. I ended up mainly using Bamboo. They are soft but tough due to the fibers running through them. If I cut the bamboo on a cross cut the fiber ends are like dots on the pick give a rough 'strike' against the string like a Herco pick. I started making them asymmetrical shape to give 3 different radius corners. Each corner has a slightly different sound. Here is a pick of some hardwood picks and another of Bamboo Picks where you can see the straight grain (smooth) and cross cut grain (rough like a Herco). Hard to see here that they are slightly curved to follow the contour of you thumb