Bip39 length https://www.4shared.com/s/fAf7kF4dLku It's important which the mnemonic sentences are generated from randomly chosen figures! These figures can be produced in a number of various ways, which might be described in other posts in this article, like "What on earth is an RNG" and Seed Phrase Technology. This extra complexity https://giphy.com/channel/ebliciwsah