‘Cones are ceramic objects that you fire in the kiln together with the wares. They are specially blended materials that bend after receiving a fixed amount of heatwork. The higher the number, the more heatwork is required to bend the cone. Usually, three cones are used together. The middle one is the target heatwork, the higher and lower ones are to check if the kiln has over or under fired, both of which can drastically affect the quality of the products.’