David Aguilar, an 18-year-old from Andorra, has always had a knack for Lego.

He built cars. He built planes. And when he was nine years old, he designed a prosthetic arm for himself.

Aguilar’s right arm hadn’t fully developed when he was born, resulting in stunted growth for that arm.

“Growing up, it was always quite annoying because I received a lot of comments like, ‘oh, you don’t have a hand,'” Aguilar said in a video on the YouTube channel Great Big Story.

He came to make lighthearted humor about it; he plays EDM music and his DJ name is “Hand Solo.”

The first arm wasn’t strong enough, but Aguilar waited nine years before building another. This model, which he called MK1, allows him to move it from the joint and do activities such as push-ups.

He immediately went to work on a second.

The MK2 model is like the upgraded Spiderman suit Peter Parker gets at the end of Spiderman: Homecoming. The first was fine; the MK2, though, looks sleeker, has a battery that works as a bicep, and a fishing cable that helps him close the hand and stop the arm.

People at school were amazed – after all, as David said in the video, how can you build a working arm out of Lego pieces?

“I was a normal guy, and when I built the arm, everyone as like, ‘you’re awesome, you’re really smart,” he said. “They told me they are really proud to be my friends.”

As of Saturday afternoon, the video had more than 480,000 views.

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