Subway trains in Stockholm have a Pac-Man easter egg hidden in their air vents, and seems as if they have been there a while.

Easter eggs can be one of the most fun things about a video game, especially if a lot of thought has been put into them and studios are able to include fun elements from other seemingly unrelated games. It can also give you more reason to replay a game over and over with the hope that you'll find something new or see something you missed the first or even second time around.

Sometimes you might be lucky enough to stumble upon a video game easter egg out in the real world. There's one very cool, but also very well-hidden one to be found inside Stockholm's subway system. A Pac-Man easter egg that is a part of some of the trains' air vents. The cool nod to the iconic video game was spotted and shared on Twitter by Fabiano Souza.

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“Cute Easter egg in the new subway train in Stockholm,” Souza tweeted with a photo of what he found. The grate on the train, which is largely filled with regular old round holes, has four modeled after Pac-Man. Well, one that takes the shape of the main character himself, and three more are the ghosts chasing him. It's unclear how long the easter egg has been there as a similar photo was shared on Reddit earlier this year, and the same again late last year.

Quite a few people have highlighted a troubling omission from the neat little easter egg. The missing fourth ghost. Souza has revealed in the replies that the fourth ghost is off to the right not pictured. This could actually be a sign that the easter egg was implemented by someone with a deep knowledge of Pac-Man. Three of the game's ghosts were coded to corner Pac-Man, while the fourth's pattern was supposed to be more random.

Stockholm's Pac-Man air vents are just the tip of the iceberg when it comes to the Swedish capital's subway system. Many of them are elaborately decorated, including one that has an 8-bit video game theme which features even more nods to Pac-Man as well as a few Mario references. One for the bucket list if you can ever make it to Sweden.

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