 Several critics wrote that Portal 2 excels in teaching the player to solve puzzles ; in a review for the New York Times , Seth Schiesel wrote , " Somewhere out there an innovative , dynamic high school physics teacher will use Portal 2 as the linchpin of an entire series of lessons and will immediately become the most important science teacher those lucky students have ever had . " Mathematics and science teachers wrote e @-@ mails to Valve to tell them how they had included Portal in their classroom lessons as part of a project to promote the " gamification of learning " . Portal developers Joshua <unk> and <unk> Malaika led a team within Valve to explore ways of using Portal 2 for education . This led to the development of Puzzle Maker , a level editor for Portal 2 players , built from the professional tools used to develop the game . <unk> and Malaika did not want to design curricula themselves , but wanted to provide educators with tools for creating lesson plans . Hammer , the only tool freely available before the release of the built @-@ in level editor in 2012 , was difficult for educators to learn and understand . Valve gave Puzzle Maker an easy @-@ to @-@ learn interface and the ability to share puzzles and lesson plans . The tools were developed with a mathematics teacher and her students . This formed the basis of a new " Steam for Schools " initiative launched in June 2012 , under which educators could acquire Portal 2 and the Puzzle Maker software free of charge for classroom use through its " Teach with Portals " program . As of November 2012 , Valve estimates that over 2 @,@ 500 educators are using the " Teach with Portals " software within their lesson plans . 
