Well, firstly, I think we should probably throw the entire patent system out. It's a hindrance to innovation. <--- yes, that's a period In your case, I think y

Well, firstly, I think we should probably throw the entire patent system out. It's a hindrance to innovation. <--- yes, that's a period In your case, I think you argue that there is nothing special about lava stones, and in fact, dirt/mud contains many stones. Probably, including tiny lava stones, whose only real difference with the additional lava stone bits is size. So, adding stones is not very novel. There's also not much difference between a lava stone and a non-lava stone; if I can put in a non-lava stone, I can probably just as easily put in a lava stone. Is it not obvious that if I can put a quartz into a mud pie, I could also put a lava stone? I guess the general strategy is to find the more general pattern and then show that the patent is just a specific instance of a larger, known pattern.