The UK is planning to introduce a new 12-sided £1 coin that it says will be the hardest in the world to fake. Pending approval, the dodecagonal prism will replace the current cylindrical design, and will feature a number of security measures to prevent counterfeiting. The Royal Mint, a government-owned company responsible for minting all the UK's coins, says the new bi-metallic coin will be the first to integrate iSIS, a technology introduced last year with three layers of security.

Although it's somewhat vague about how the new technology works, the Royal Mint says iSIS embeds "proven" security technology from banknotes into coins. The idea is to enable automated verification of authenticity through "overt, covert, and forensic" markings, so a vending machine, for example, will know if a coin is real by more than its weight, shape, and size.

There hasn't been a 12-sided coin in circulation in the UK since 1971, when the country decimalized its currency and retired the threepenny coin. The UK decided to replace its £1 note with a £1 coin in the eighties, and since then it's had a fairly simple circular design. The current coin is apparently easy to counterfeit —HM Treasury suggests as many as three percent of the £1 coins in currently in circulation are fakes. The new coin isn't expected to enter circulation until 2017.

Correction: This article originally referred to the new coin as a "dodecagon." While the two-dimensional shape on each side of the coin is indeed a dodecagon, the fact remains that coins are three-dimensional objects. As such, the correct way to describe a 14-faced shape is as a tetradecahedron, and this particular tetradecahedron is a dodecagonal prism. The article has been modified to reflect this.

Thanks, Trevor!