How could an extra thumb be helpful? Designer Dani Clode wanted to know. She used a 3-D printer to bring her design for the Third Thumb to life in 2017. The extra thumb is strapped to the side of the wearer’s pinky and controlled with a pair of sensors under each big toe. The device is strong enough to squeeze a lemon and dexterous enough to use a paintbrush.

According to a new study, the human brain is quick to learn how to use an extra helping thumb. That’s a good sign, as devices like the Third Thumb could help people who have lost fingers—or even limbs—regain mobility.