A toy designer with a passion for 3D printing is changing the lives of disabled children around with world with a line in tailor-made prostheses.
Eight-year-old Juan Moyolema, born without the lower part of his left arm, was thrilled to receive a new hand from Madrid-based Ayudame3D.
It was only a few minutes before he was testing the new hand, slowly flexing at the elbow to close the grip.
His sister and two brothers both watched nervously and then with joy, as he gave the new 3D prosthetic a test drive.
"It's going to help me pick things up, things like toys," he said, grinning, before tentatively shaking the hand of Guillermo Martinez, the founder of Ayudame3D.
Mr Martinez, 27, began tinkering with the devices as a hobby but after a 2017 trip to deliver prostheses to an orphanage in Kenya's Rift Valley, he decided to dedicate himself full-time to the initiative and set up Ayudame3D.
"The five arms that I took (to Kenya) ... worked so well, so perfectly, that I asked myself: 'How can I just stop here?'"
He works out of a converted shipping container crammed with dozens of printers, prototypes and off-cuts.
Prosthetic arms are based around three core designs reaching to the wrist, elbow or shoulder, and are made of plastic.
Four years on, Ayudame3D has grown and delivers up to 250 arms a year all over the world, free of charge, to anybody who requests one.
Mr Martinez did not give an exact figure for how much they cost to make, but said it's a tiny fraction of a traditional prosthesis, which can cost up to $40,000.
His organisation relies on donations and awards, and also gives companies 3D printing courses.
He now wants to expand Ayudame3D's reach and range of products.
"We just want to help as many people as possible. If we are in 50 countries this year we hope to be in twice as many next year."
In the early days of the Covid-19 pandemic when face masks were scarce and many health staff worked unprotected, the group manufactured and donated some 20,000 plastic face shields.