You shouldn't ever try to copy money.

Also: You physically can't do it.

In a video from the series That Wikipedia List we first spotted on Gizmodo, Wendover Productions explains that currency has a highly secretive, built-in system that alerts technology like photocopiers and Photoshop to stop working on it. Because counterfeiting is highly illegal, a photocopier will refuse to copy a bill, and Photoshop will reject the image.

The pattern depicted in blue dots in the screengrab above is called the EURion Constellation, and was a security measure found in multiple international currencies. However, now there's a new counterfeit-stopper on the block ... and no one knows much about it.

"More recently, copiers have moved to a system called the Counterfeit Deterrence System, which is incredibly secretive and effective," the video says. "Nobody is really sure how it works. And while the EURion Constellation might be part of it, these security features make it even more difficult to copy bank notes."

Learn more in the short video below: