I've noticed several people here making physical notes or coins with Bitcoin values and I'm wondering how they do that. I'm new to Bitcoins but have been making monetary-themed art for many years and it's something I might like to try myself sometime. Making the physical object and its design is easy, but what I'm confused about is how to transfer the actual monetary value from my personal client software to this piece of paper with a number on it. How do you "send" Bitcoins to a physical object instead of another alphanumeric payment address? And do physical Bitcoins have to have a QR code?