Here is something you can do with those thick in the middle pieces. You may not want to attempt this right now, but if you keep knapping, then at some point down the road you will start thinking about fluting. Hang on to your skinny pieces that have the bulging middles. They are really good for practicing fluting. It is easy to set up the fluting platform on these thick middle pieces. And chances are when you are learning to run big ol flutes, you are going to bust quite a few pieces. So if you break one of these, it is better than breaking a really nice piece you put a lot of time in.