One of the keenest senses of accomplishment I felt as a kid was completing a LEGO Millennium Falcon. I was probably no older than eight, and I was tasked with entertaining my four-year-old brother in the process, so following all of the instructions and actually creating a finished product was fairly impressive. But now that feat looks weak, because one of Renault’s designers used LEGOs to design the hybrid transmission available on the PHEV and hybrid Clios, Capturs, and Meganes.

You can listen to Nicolas Fremau, Renault’s Hybrid Architecture Expert, talk about it in the video below:

“When I saw my son playing with LEGO Technic sprockets at home, I said to myself, ‘well, it’s not so far from what I’d like to do’. So, I bought what I needed piece by piece to have all the assembly elements,” Fremau says. “Renault has always been a very open company, especially when it comes to research, but the day I brought the model to the Gérard Detourbet and Rémi Bastien, I didn’t know how they would react. They walked around the model, they touched it and they felt that we had a real object. And I will always remember Gérard Detourbet’s remark: ‘If we can make it in LEGO, it will work!’”

That’s certainly one way to think about it.

The model itself took 20 hours to complete, according to Fremau, plus a following 18 months to build the LEGO creation into a real, functioning vehicle. Apparently, the tactile nature of the LEGO set allowed Fremau to play with things, take them apart, and try out designs that he wouldn’t have really thought of on paper. Having a small but functional product to experiment with in the physical plane was definitely a benefit.

The resulting technology is actually pretty cool. The transmission has no clutch and is connected to two electric motors, plus the engine, which provides a smoother, more optimized ride. It has an output of 158 horsepower or 118 kW, and Renault claims that 80 percent of all city driving can be handled on electricity alone—which is impressive, considering the fact that the Clio Hybrid has a teeny 1.2 kWh battery.

But that’s the benefit of working with a small, functional model—you can optimize a car’s components in ways that never seemed possible.