First functional LEGO® prosthetic arm
David Aguilar
First first
Andorra ()

David Aguilar (Andorra), who was born without a right forearm, designed and built his own fully functioning prosthetic arm using bricks from a LEGO® Technic helicopter set (#9396), completing the first version – named MK-I (Mark 1), after the suit built by comic-book hero Iron Man – in 2017. The purely mechanical prosthesis featured a moveable elbow joint and a grabber for picking things up, which he actuated by bending his elbow. Aguilar, aka "Hand Solo", has subsequently refined his designs a number of times, and his most recent model, MK-IV (Mark 4), is a motorized arm with five fingers that he controls by making subtle movements of his residual arm.

Aguilar began designing LEGO arms from the age of nine years old, and now has a collection of self-built arms. His passion for the construction toy led him to study bioengineering, which he currently does at the Universitat Internacional de Catalunya in Spain. His dream is to create affordable prosthetics for those not in a position to pay for the fitting and maintenance of a traditional prosthetic.

MK-I was built using pieces from the LEGO Technic Rescue Helicopter set (#9396); MK-II from the Air Race Jet (#42066); MK-III from the Bucket Wheel Excavator (#42055); and MK-IV from the Rough Terrain Crane (#42082).