Scientists at MIT built a 16-bit microprocessor out of carbon nanotubes and even ran a program on it, a new paper reports.

Silicon-based computer processors seem to be approaching a limit to how small they can be scaled, so researchers are looking for other materials that might make for useful processors. It appears that transistors made from tubes of rolled-up, single-atom-thick sheets of carbon, called carbon nanotubes, could one day have more computational power while requiring less energy than silicon.

“This work is particularly exciting because carbon nanotubes are one of the most promising supplements in the future of beyond-silicon computers,” Max Shulaker, the study’s corresponding author and assistant professor at MIT, told Gizmodo.