The polystyrene rings are HALF rounded. So the ring can be mounted on a flat surface.They can be painted or can be decorated with a multitude of craft and modelling materials as well as floral items - You can create a fantastic advent wreath, or sweet / chocolate wreath (cover the ring with your choice of tissue paper or other decorative covering and attach sweets or chocolates using plastic cocktail sticks to make a trendy edible centrepiece.