“Graffiti (play)Ground” is an interactive floor that invite participants to play with their bodies to co-create a real-time graffiti on the floor. The system turn each person into a human paint brush using projection mapping on the physical surface. The challenge of the play is that whenever two or more people group together their brush will become more pronounced and the other participants with lesser number of people will not be able to paint! So the participants will collectively negotiate with each other to create the final Graffiti in peace or they can go to war with each other. “Graffiti (play)Ground” is a platform for social play with so simple rules yet can set off unlimited complex possibilities. It ask the question that pierce into human nature whether to maintain one’s individualism or give into collectivism and sacrifice personal freedom. To be or not to be?