I would replace “art” for “skill “. In another life I did boat building. The same techniques used for forming the compound curves in boats and half-models of boats were used here. Fusing this technique into ceramics was the “creative “ part. Given that, it doesn’t take a lot of skill to make a rectangular form. It does take some perseverance to smoothly encase that form with clay. I thank you for your kind words but I’m trying to remove the mystery and put it within the grasp of people who might like to try. In their efforts they may move the technique forward with new design.