Within a few hours, they had modified the printer to draw simple, short-term doodles on skin. Not satisfied with temporary tattoos, the students added parts from a standard tattoo machine. The result: a printer that can give you permanent tats.

After the invention was tested on simulated skin, volunteers lined up for the honour of being the first to get inked. “A lot of people were excited by the idea of being the first human tattooed by a ‘robot’,” writes team leader Pierre Emm in the instructions they posted online.