The majority of heirloom tomatoes are indeterminate, although some determinate heirlooms exist. Many also choose to plant and grow heirloom vegetables and to raise heritage livestock. There is some controversy as to whether Green Zebra should be considered an heirloom tomato. Quite a few seed merchants and banks provide a large selection of heirloom seeds. "Amish Snap" is the only true heirloom snap pea. Decorah is also home to Seed Savers Exchange, an heirloom plant farm and preservation organization. The revolution made the production of carefully executed replicas of admired heirloom pieces possible. Quilting also frequently employs the use of recycled scrap or heirloom fabrics. It is available from growers who specialize in heirloom plants. Both sides of the DNA in an heirloom variety come from a common stable cultivar. Another worldwide alternative is to submit heirloom seeds to a seedbank. Modern hybrids focus on improving disease resistance over the heirloom plants. Kris knives are important items, with many heirloom kris holding significant historical value. Mason explains that he needs an old family heirloom, a moonstone. The definition and use of the word "heirloom" to describe plants is fiercely debated.