They’re impractical, but checkout Physical bitcoins: https://medium.com/the-capital/everything-you-need-to-know-about-physical-bitcoins-ceaab58f18c6 https://med

They’re impractical, but checkout Physical bitcoins: https://medium.com/the-capital/everything-you-need-to-know-about-physical-bitcoins-ceaab58f18c6 https://medium.com/the-capital/everything-you-need-to-know-a... I did say -technically- and I do mean that - I’m not suggesting this is practical.