When computer engineer Patrick McConologue passed Leo Grand sitting in the street, he saw something in the homeless man most of us would've missed.
Patrick thought there was 'something different' about homeless Leo, so he gave him an ultimatum to turn his life around for good.
Patrick, 23, offered Leo $100 on the spot or the chance to train as a computer programmer every day for an hour.
While most in his position would've taken the quick cash fix, Leo chose the training - and he's now about to release his very first app.
Patrick bought Leo, 37, three textbooks and a laptop, before teaching him the language of computers.
With Patrick's help, Leo has designed his own car-sharing app for New York, called 'Trees for Cars', which went on sale on Tuesday.
The achievement marks an incredible and unexpected turnaround for Leo, who had been sleeping in New York shelters for two years before the life-changing offer.
Leo hopes to get a permanent job and a place to live soon, having taken so quickly to Patrick's teaching.
Patrick said Leo was a very fast learner. Describing his unlikely student, he said: 'The speed at which I’m going through these lessons is insane.
'We barely cover things twice. His memory is really, really good.
'He very clearly stands out and when I saw him he was benching boat chains and it was clear that this guy is trying to do something big… it wasn’t just working out, it was intensity it was just drive.'
Patrick added: 'All homeless people are mentally ill, lazy, unintelligent — that's the stigma.
'It doesn't really matter about your living arrangements as long as you've got the mindset to do it and the will.'
Leo said he thought he was the subject of a cruel prank when he was first approached with the offer.
He said: 'I know how to build a server now, and I'm learning back-end design.
'I'm much more popular now.'