This is a hot water bottle design, the hot water bottle as the item held in the hand, we will naturally touch it repeatedly, so I will make a connection between the behavior of the hot water bottle and the touch perception of the moss. The gap of the hot water bottle looks like an ordinary concave decorative pattern when the water is not filled. When the water is injected, the fluff in the slit is spread by the water to form a convex pattern. When the user's hand touches the fluff of this strip, it will repeatedly touch it because of the familiar touch, thereby constructing a perception image that associates with the moss in the gap.