Superhero movies are all the rage these days, as comic book companies find new life on TV and in cinema. They have never been so popular (or profitable).

According to RAM Tracking, a GPS fleet tracking company based in Leeds, United Kingdom, one fan used the company’s software to paint his favorite superhero logos. His canvas? A map of London.

While some of the drawings are a little rough due to the nature of being confined to established street routes, some of them bear striking resemblance to popular superhero logos, including Batman, Superman, the X-Men and even Thor’s hammer, Mjolnir.

According to RAM, one of its data analysts noticed a client taking a consistent number of irregular journeys. Upon investigation, RAM determined a London-based electrical contractor was using the vehicles GPS tracking software to record the images over multiple weekends. Some of the images reportedly took several weeks to produce.

“We certainly weren’t expecting a client to get so creative with our software—especially as our services are primarily used as a tool to help decrease business operating costs,” said Chris McClellan, CEO of RAM Tracking. “GPS technology has sky-rocketed in use over the last five years, and it is continuing to see a significant growth for both personal and commercial use. ‘GPS street art’ is something that we had seen with the use of running and fitness apps, but it came as a pleasant surprise when it was spotted in our system.”

According to RAM, the contractor wished to keep his identity anonymous, but he said, “It took a lot of preparation, but it was a lot of fun to carry out. It was great to see that I could create pieces of undercover art, with the help of RAM’s route replay feature, which I access every day. I wasn’t expecting anyone else to notice, so when I got the call from RAM Tracking enquiring into the activity, I was surprised. It made me smile knowing that they had seen my antics!”

Unfortunately, none of the summoned heroes have answered the call, but you can see all of the GPS street art from this contractor above.