David Aguilar, an Andorran inventor born with Poland syndrome, constructed a LEGO Technic‑based prosthetic for eight‑year‑old Beknur Zhanibekuly in August 2021.
His own right forearm never developed beyond a stub, forcing him to confront ridicule in school; he turned LEGO bricks into a laboratory at nine. Too heavy, the first prototype folded under its own weight.
In 2017, at eighteen, Aguilar released the MK‑I, featuring a pivoting elbow and a grabber; the design earned a Guinness World Record for the first functional LEGO prosthetic arm. The success spurred a quest for a child with a similar need.
Beknur’s mother, Zaure Bektemissova, heard of the invention via social media and flew from France to Andorra in August 2021. Aguilar, assisted by his father Ferran, engineered two models—MK‑Beknur, a foot‑controlled arm, and eMK‑Beknur, a stylus‑enabled device for touchscreens.
Both models earned separate Guinness titles in 2021 as the first functional foot‑controlled LEGO prosthetic and the first with a stylus, with the entire kit costing just €15.
Aguilar now shares building instructions online and plans a free workshop series in 2024 to democratise low‑cost prosthetics worldwide.