Bip32 And Bip39. From this place ahead the seed could be published on paper or spoken over telephone and this opened up new, Actual physical ways of backing up the seed (multiple paper copies in various places, durable copies on steel plates with more security from fire/flood and many others.). https://7bookmarks.com/story18441146/bip39-word-generator-examine-this-report-on-bip39-explained