We turned to something everyone would have in their pockets—a phone—and combined it with the power of Android to build Paper Planes, a second-screen experience that enabled users at the keynote and those live streaming it to, fold, stamp and throw planes from their phones into a virtual world on the 50-foot mainstage screen in real time. By waving their phones like a net, users could catch other planes to see where they had traveled and stamp it with their own location before throwing it back, connecting with one another in a new and exciting way.

Paper Planes was created using WebSockets and powerful funnel servers over the Google’s Cloud Platform and App Engine. This seamlessly connected 7000 attendees with users live streaming from around the world, showcasing their connection—a giant flock of paper planes—on the 50-foot mainstage screen in real time. Anyone could join Paper Planes by simply visiting the URL on their phone. Planes were stamped, thrown and caught by using data coming from the phone’s accelerometer, gyroscope and GPS. Planes’ trajectories were tracked via geocode headers so users could follow their planes’ journey across the world.

We used Javascript and WebGL to create the zen-like virtual world of Paper Planes. We wrote custom flocking algorithms and deployed complex 3D shaders to render this world in real time, optimized to avoid any lag. Dynamic, animated location displays were paired with a responsive audio design to keep the experience perpetually renewing.

Paper Planes also challenged users to interact with their phones like never before. They literally mimicked the gesture of throwing a plane with their phone to cast it into the world, as well as swung their phones like a net to catch another person’s plane.

Over the course of I/O, there were over 212,000 planes thrown from 158 countries. The average time spent with the experience was 2 minutes and 16 seconds. After I/O, we opened Paper Planes to the world as an Android Experiment on the International Day of Peace in September. Since then, over 4 million people have used the app, throwing or catching over 14 million planes from over 160 countries in the world, with over 46 million stamp interactions.