Soon after the release of the 2007 hit video game Portal, the developers at Valve  began receiving emails from math and science teachers across the country who were using the game in their classrooms. Some worked at private high schools, others at urban middle schools. A few taught at the college level. All were eager to share their enthusiasm for Portal with the development team.
Valve had never thought of itself as being in the education business, and the company wasn’t sure how it could support teachers. Their expertise was in game development, not in learning, they thought. But Valve has always been inspired as much by conversations happening outside of the field of video games as within it, so they started talking to educators to find out more. What did teachers consider to be qualities of optimal learning environments? What did schools think of student-directed learning?
These conversations led Valve to conclude two things: that a good education researcher would probably make a damn fine game designer, and they could do better when it came to making tools for educators. So two of the original members of the Portal team, Joshua Weier and Yasser Malaika, formed a small unit within Valve to explore the educational potential of the 2011 sequel, Portal 2 . The ongoing development work on what would eventually become Puzzle Maker, which took the professional level tools used by the Portal development team and transformed them into a level editor for the community of Portal 2 players, gave it a built-in model for skill acquisition.
Puzzle Maker took what was already a powerful tech toolset and made it more expressive so that young people, while using it, would feel fully capable of producing a game. Along the way, Valve worked with Lisa Castaneda, a middle school math teacher at a local school, and brought in students early and often to get feedback on the toolset during its development. They also launched the Teach with Portals  initiative, where teachers can find lesson plans and community-created resources to support integrating Portal 2 and the Puzzle Maker into their curricula.
Since its launch in June 2012, the Teach with Portals initiative has brought Puzzle Maker to over 2,500 teachers worldwide. Valve still doesn’t consider itself as being in the education business, but the education version of Portal 2 Puzzle Maker continues to be updated with new features--the last release was less than a month ago.
Katie Salen is the Executive Director of Institute of Play and a Professor in the School of Computing and Digital Media at DePaul University. Institute of Play  is a not-for-profit design studio that pioneers new models of learning and engagement.
Corrections: Valve developer Yasser Malaika's name was spelled incorrectly in the original version of this article, we regret the error. Also, The Teach with Portals initiative has brought Puzzle Maker to over 2,500 teachers worldwide, not nationwide as was originally reported.