Acoma potters mix their clay with ground-up bits of broken, fired pots. This prevents the new pot from cracking in the firing process. A pot is made by coiling clay in a circular manner and pinching the coils together, smoothing them to form the sides of the pot. The pot is hardened ("fired") in an open fire. Once a pot is fired only a few elements are used to form designs—lines, scrolls, and geometric shapes—but there are endless variations so that every pot is different. Mixing iron ore with the beeweed plant makes a black paint. Paint is applied with a chewed yucca leaf to the surface of a pot that has been covered with thin white clay slip.