Bip39 Seed To Private Key. From this position ahead the seed could be composed on paper or spoken around phone and this opened up new, Bodily ways of backing up the seed (various paper copies in numerous destinations, resilient copies on metallic plates with added security from hearth/flood etc.). Nonetheless, https://bookmarkfriend.com/story18624077/bip39-docs-about-12-word-seed-phrase-generator-with-balance