Sitting in a classroom with a number of ex-cons–two former drug dealers, a murderer and an identity thief–we asked a simple question: Where does creativity come from? For those who had just spent time in prison, the answer was simple: scarcity.

“Look around this room,” we were told. “There are about 100 weapons in here. I could kick in that sink and make a knife. I could melt the plastic on that chair and make a razor. The pipe work in this building is an arsenal of weapons.”

The more we spoke with innovators in the black markets and informal economies of the world, the more we heard responses like this, which reflect the ingenuity and hustle of those who operate in the underground.

To hustle is to see things for more than what they seem at first glance–to be opportunistic, resourceful and alert to every little detail around you. And these traits are as evident in fringe economies and informal markets as they are in Silicon Valley tech hubs and startup incubators.

From hackers building crypto-currencies or mobilizing global protests to gangs like the Latin Kings creating powerful brands, the question is how we in the formal economy can learn from the misfits of the world. At a time when even ISIS has an app and a social-media strategy, we believe that there is value in paying greater attention to the creativity emerging from the underground.

Clay and Phillips co-authored The Misfit Economy: Lessons in Creativity From Pirates, Hackers, Gangsters and Other Informal Entrepreneurs

This appears in the June 29, 2015 issue of TIME.

Contact us at editors@time.com.

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