Radical circle is an innovation approach, alternative in comparison to innovation teams and innovation communities, superior to these when detailed managerial guidance is not readily available because of high uncertainty, high ambiguity, or both. Through an empirical case analysis of Angry Birds, the video game, we strengthen earlier radical-circle research findings on how a common sense of malaise with a current situation and dominant visions sometimes a small group of creative individuals meaningfully together, each volunteering to contribute much to change situation and dominant meaningfully vision. We find in this case that radical circles were more fluid in their membership and boundaries than what these earlier studies have found. There was considerable change over time in both the radical circles and visionary innovation. After Angry Birds's launch, a huge and very active brand community ensued, with radical creativity, with innovative community members contributing meaningful new inputs both for free and for global market and industry transformation. We call for further research on why and how line-up changes in radical circles in between times of original visionary innovation and later-phase market and industry transformation may matter. We also call for further research to study in what kinds of situations, why, and how radical circles are a good approach to mobilize extra-organizational volunteers for visionary innovation of new-to-the world products or processes.