My goal for the higher walls is so that it will run a little hotter, but that's why i left that gap between the shisha and the screen. plus it prevents the shisha from getting burned from direct contact with the coal. The purpose of the spirals inside the hookah is so that it will cause the smoke to have more movement before it hits the water, and my idea is that it will make the smoke thicker and cooler. The threads simply came from the idea that im sick of loosing my rubber grommets and that would eliminate the need for that. Plus i added the holes on the side of the bowl so that more smoke can be pulled in each hit.
Im no bowl expert, this is just my over engineered idea of a hookah bowl. Its a result of a collection of ideas / issues i have with hookahs. All of the possible solutions combined into one bowl.