This is an archived article and the information in the article may be outdated. Please look at the time stamp on the story to see when it was last updated.

NEW YORK (PIX11) – On Tuesday, 36-year-old Queens native Leo Grand launched his mobile app, “Trees for Cars.”

The app is designed to get people to carpool and reduce the amount of CO2 in the air.

Leo is homeless, and just three months ago he had no idea how to code.

Patrick McConlogue, a 23-year-old programmer, would pass Leo on the street  on his way to work each day. So one day, Patrick offered Leo $100 or the opportunity to learn how to code.

Every day for the past three months, the duo met to study and create  the app.

Patrick and Leo’s journey, followed by 50,000 people on Facebook, is only just beginning.

“He writes every line, and he understands every line,” Patrick said of his now friend Leo.

“If you’ve been blessed with a talent or skill…pay it forward, teach somebody something. Even if you just one help one person, the fact that you even tried is a step in the right direction,” Leo said.