When a homeless man was accidentally killed by a train on 11/08/18 in The Dalles, Oregon, no one realised how many people it would effect. The man was a computer programmer called Terry Davis and he was on a mission from God.

He'd designed an entire operating system called Temple OS and according to Terry its creation had been a direct instruction from God himself. As a fellow programmer explained it, 'you can imagine how over time one man might build a house, but this is like building a sky scraper, on your own!' And this was all done while Terry battled a diagnosis of schizophrenia.

Aleks Krotoski searches the emails, web posts and live streams to piece together the life of a remarkable individual whose work touched so many and is now celebrated not just as a technological achievement but an artistic one.

Producer: Peter McManus
Researcher: Elizabeth Ann Duffy