We'd all be printing money if it were easy, and that's why government folks try so hard to make it hard. This crazy visual effect could be the latest trick up their anti-counterfeiting sleeves. And man is it awesome to watch.

The measure demonstrated in the video above is something called a moiré pattern, the effect you get when you look at one grid through another. Usually, the result is a mesmerizing but meaningless geometric pattern. With some clever design, though, and printers that can lay down ink at the insane density of 9,754 dots per inch, researchers from the École Polytechnique Fédérale de Lausanne (EPFL) have whipped up a more practical—and crazy—result.

Moiré pattern security is already on some bills, but these new hi-res versions of the effect can display discernible images and letters that make identification a breeze for actual human eyes. And even if a counterfeiter was to try and replicate the visual puzzle, even the slightest imperfections in the high-density dot-laying would scale up to extremely noticeable distortions.

You can never really beat counterfeiters—you can only stay a step ahead. But now that holograms aren't as hard to replicate as they used to be, these little illusions are a promising way to keep the lead. For a little while, at least. [Phys Org]