KEYS have been around for a long time. The earliest, made from wood, date back 4,000 years, to the ancient Egyptians. The Romans improved them a bit by making them from metal. But there, more or less, they have stayed. Electronic card-keys aside, a key is still, basically, a piece of metal sporting a series of grooves, teeth and indentations which, when inserted into a keyway, line up to move pins
![A 3D-printed key that can’t be copied](https://cdn-ak-scissors.b.st-hatena.com/image/square/a89dd60f622ebff88d0631584a248e9f30543cf0/height=288;version=1;width=512/https%3A%2F%2Fwww.economist.com%2Fimg%2Fb%2F595%2F335%2F90%2Fsites%2Fdefault%2Ffiles%2Fimages%2Fprint-edition%2F20170415_STP004_0.jpg)