Appeel is a virus spreading through interacting individuals, it demonstrates the basic principles of interactivity largely reliant on people’s behaviour. A surface is covered by a large number of coloured stickers, positioned in a grid. People can remove stickers, leaving white spots in the layout, as a result individually and collectively changing the walls appearance. These stickers then take on a life of their own, as they spread, extending beyond the installation itself, infiltrating private space and merging the boundaries of public and private space.